The TEDx Users Guide to Dr Caroline Leaf

On the 4th of February 2015, Dr Caroline Leaf gave her debut TED presentation, at TEDx Oakes Christian School, California.

Most TED watchers wouldn’t have heard of her before, but Caroline Leaf is a well-known name in western Christendom. She has spoken from pulpits on every continent. She’s authored one of the best selling books in the Christian market and has her own TV show on cable in the US. She’s followed by more than one hundred thousand people on Facebook, and she’s even run her own conference, with another in the pipeline. She’s a mega-star in the Christian world.

So who is this woman with the stiletto-heels and slick presentation? What was her training and background? How did she make it to the TED stage?

This aim of this post is to provide some context and background for those in the TED universe who have seen Dr Leaf’s TEDx presentation, and want some more information in assessing her TEDx debut, and indeed, the global Caroline Leaf phenomenon.

This review will be in four main parts: first I will give some basic information on Dr Leaf, I’ll compare Dr Leaf’s TED talk claims to her published research results and to some basic neuroscience, and lastly I’ll outline Dr Leaf’s general work and it’s accuracy compared to current science.


Dr Caroline Leaf was born and raised in South Africa, where she completed her school education and went on to attain the following degrees:

  1. Bachelors of Science (Logopaedics) – University of Cape Town 1985
  2. Masters in Audiology and Speech Pathology – University of Pretoria 1990
  3. Doctor Philosophiae (Communication Pathology) – University of Pretoria 1997 (

Officially, Dr Leaf is a qualified as a communication pathologist (which is a specialized combination of Speech Pathology and Audiology – see also:

Dr Leaf worked for a number of clinics and school boards as a communication pathologist in the few years following the completion of her PhD (

Dr Leaf has written a number of articles for publication in minor journals (see Three of her papers were published in a small Medline indexed journal, “The South African Journal of Communication Disorders”. These are:

  1. “Mind-Mapping approach (MMA): a culture and language “free” technique”, 1993 (
  2. “The development of a model for geodesic learning: the geodesic information processing model”, 1997 (
  3. “An alternative non-traditional approach to learning: the metacognitive-mapping approach”, 1998 (

The journal happened to be edited by her supervisor and co-author, Dr Brenda Louw (see, though I’m sure the selection of her articles for this journal was purely on merit.

Dr Leaf states on a number of occasions that she is a “cognitive neuroscientist”, and “a scientific and Biblical expert in the power of the human mind”.Leaf Cognitive NeuroscientistAbout Dr Leaf

This is despite the fact that Dr Leaf:

  1. does not have formal qualifications in neuroscience,
  2. has not worked at a university as a neuroscientist,
  3. has not worked in any neuroscience research labs,
  4. has not published any papers in neuroscience journals, and
  5. has not had any formal theological training.

Given the weight of evidence, Dr Leaf would be better described as an academic speech pathologist and lay preacher rather than a cognitive neuroscientist.


Throughout her TEDx presentation, Dr Leaf repeatedly made reference to the results of her own research, suggesting that her pioneering work resulted in radically improved outcomes for the students involved in her research, and that her work with students one-on-one and through teacher education profoundly changed the learning of every student in her various program.

For example, she said, “Well her IQ was 100 before the accident, it was 120 after the accident. So here with holes in her brain, and brain damage, she changed … she actually increased her intelligence. Now I’m pretty convinced at this stage, cause I’ve been working … besides her I’ve been working with lots and lots of other patients, seeing the same thing, when these students applied their mind, their brain was changing, their academic results were changing.”

Later she stated, “I wasn’t sure if this was going to have the same impact cause until this point I’d been working one on one. Well I’m happy to tell you that we had the same kind of results … The minute that the teachers actually started applying the techniques, we altered the trend significantly.”

And also, “I stand up here saying this with conviction because I have seen this over and over and over in so many different circumstances … in this country I worked in Dallas for three years in charter schools, and we found the same thing happening.”

However, her published results differ significantly from her claims.

The first research that Dr Leaf spoke of was of the sixteen-year-old girl who was the victim of a motor vehicle accident. This particular girl was Dr Leaf’s prime patient. The case study of this patient was presented in Dr Leaf’s unpublished Masters thesis, and was discussed in more detail in Dr Leaf’s paper, “Mind-Mapping approach (MMA): a culture and language “free” technique” [1], thought it should be noted that no statistics were published in this paper, and on the third page of the article, Dr Leaf admitted that the result could actually have been spontaneous recovery rather than her own intervention.

Dr Leaf did further work within a number of schools for her PhD research. Dr Leaf compared the academic results for three schools for the years 1991 and 1992 to the results for 1993, during which she introduced her mind mapping approach (MMA). Generally, the results for 1993 were better than the results for 1992, which seems to indicate that Dr Leaf’s MMA training was effective. However, the results from 1991 to 1992 were already improving without her input [2: p182]. The difference in average marks between 1991 and 1992 was 1.76%, while the difference between 1992 and 1993 (the introduction of Dr Leaf’s MMA) was only 2.19%. If Dr Leaf’s program really was the cause of that improvement, then her program only resulted in a 0.43% improvement on average.

I have reproduced Dr Leaf’s original graph of the average overall results obtained in her PhD study. While Dr Leaf’s original graph makes her data look spectacular, when appropriately rescaled, the data looks quite ordinary.

Leaf1997 Thesis overall academic trends


At best, Dr Leaf’s program gave the already positive momentum of the students a gentle nudge.

However, it should be noted that her program may have also hindered some students. Dr Leaf notes in her analysis: “The results obtained indicate that in general the academic trend in the three primary remedial schools was altered with the introduction of the MMA methods in 1993. Furthermore, it appears that the most positive response occurred in phase one (grades 1 and 2, standard 1). A positive response also occurred in phase two (standards 2-4) but this change was just outside the significance level. Phase three (standard 5), by contrast, experienced negative effects with the introduction of the MMA methods.” [2: p181]

So to summarise, according to Dr Leaf’s own data, there was no clear benefit derived from her MMA program.

Dr Leaf then discussed her work in a number of charter schools that she performed in Dallas. This was part of testing of a program called the Switch On Your Brain 5-step learning process.

Dr Leaf claims that, “The Switch On Your Brain with the 5-Step Learning Process® was assessed in a group of charter schools in the Dallas. The results showed that the students’ thinking, understanding and knowledge improved across the board. It was concluded that The Switch On Your Brain with the 5-Step Learning Process® positively changed the way the students and teachers thought and approached learning.”

However, there has been no independent research into Dr Leaf’s Switch On Your Brain learning program or even the Geodesic Information Processing Theory, the theory Dr Leaf devised and on which the Switch On Your Brain program is based.

Dr Leaf published her own internal research into the program on her website. The project was a two year program involving teachers and students at a group of four schools in the Advantage Academy group in Dallas, Texas. This involved working with more than 150 teachers and 2000 students.

Despite her glowing self-assessment, Dr Leaf’s own published numbers suggest that the program is ineffective, or quite possibly a hindrance. For example, the graph below demonstrates the qualitative analysis of “content mastery” (which the paper describes as a combination of knowledge and understanding) for reading across all grades from 3rd to 12th, compared with the results from the previous year before the Switch On Your Brain was implemented. Dr Leaf omits a basic statistical analysis, but just by looking at the similarity of the scores, these results are more likely to be a chance effect, except for the 12th grade, where the previous cohort of students increased dramatically, where as the Switch On Your Brain cohort got slightly worse.

Screen Shot 2015-02-02 at 11.27.37 pm

Rather than blame her program, Dr Leaf simply shifts the blame to the teachers: “The few cases where we see drops can be linked to teacher knowledge, attitude and skills and is diagnostic.”

The full research paper that Dr Leaf published is available at if you wish to review the results for yourself.

The ineffectiveness of Dr Leaf’s program may be for many reasons, but I believe one is that it is built on a theory that relies on mind-mapping. Dr Leaf renamed her version of mind-mapping “The Metacog”, though it’s clear from her early academic work [1] that the Metacog and the Geodesic Information Processing Model [3] were based on the work of Tony Buzan. Buzan’s concept of mind-mapping has been used across multiple professional fields [4] and remains a valuable resource for brainstorming or gathering thoughts in a visual way. However, modern research (including a controlled trial within a primary school classroom environment) shows that mind mapping is a poor tool for learning [5-8].


Dr Leaf openly contradicts herself throughout her presentation, failing to realise that the stories she shared of her own patients disproved her vacuous inspirational memes.

Our biology affects each and every one of us. Our mind is a function of our brain. Our mind is to our brain as our breath is to our lungs. Put simply, without our brain, we would have no thoughts. If the structure and function of specific networks in our brains are altered, this changes our thinking. This is confirmed in everyday life – when someone suffers a brain injury or a stroke and they sustain damage to their brain, they suddenly lose the function of some, or all of their mind or body. Trans-cranial Magnetic Stimulation, Trans-cranial Direct Current Stimulation, metabolic states, prescription medications, illicit drugs, or everyday drugs like caffeine or alcohol have all been proven to change the subjects mental state through changes to the function of their brain. Any suggestion that our brain does not control our mind is simply ludicrous.

Clearly then our biology does control our psychology. Real cognitive neuroscientists have shown that our stream of thought is simply a tiny fraction of our overall neural activity, a conscious glimpse of the brains overall function [9-11], like the tachometer is for the engine in your car. Thus, our mind does not change our brain at all. Rather, it is our brain’s directed activity causing the growth of new synaptic branches to support it, something which the brain does without the function of conscious thought from the time when we were embryos.

Dr Leaf actually confirms this fact through her stories of her brain injured patients. After all, if “the mind is separate from the brain but influencing the brain”, then how could those victims of acquired brain injury lose cognitive function after their injury? If it were true that “each and every one of us is not a victim of our biology. We are a victor over and above our biology. We control our brain, our brain does not control us”, then how could those people with damage to their brains from strokes suddenly lose function?

The fact that Dr Leaf’s patients lost their mental or cognitive function because of damage to their brains directly contradicts her insistence that our brain and our mind are separate, and that our brain does not control our mind.


Considered altogether, Dr Leaf’s teaching boils down to a few fundamentals;
* Thought is the main driving force that controls every other aspect of our lives (and our physical world).
* We have full control over our thoughts.
* Thought causes stress.
* Stress is directly responsible for nearly all serious physical and mental illness.
* Therefore thought causes the vast majority of human disease, making thoughts toxic, and
* If toxic thoughts cause disease, “detoxing” thoughts will cure or prevent disease.

On first inspection, each individual postulate doesn’t seem so bad. However, when fully considered and taken to their natural conclusions, they veer into conjecture and pseudoscience, as evidenced by Dr Leaf’s published works and public appearances.

For example, Dr Leaf states in her books:

“Thoughts influence every decision, word, action and physical reaction we make.” [12: p13]
“Our mind is designed to control the body, of which the brain is a part, not the other way around. Matter does not control us; we control matter through our thinking and choosing.” [13: p33]
“DNA actually changes shape according to our thoughts.” [13: p35]

On Facebook and in interviews, this translates to:

“Our genetic makeup fluctuates by the minute based on what we are thinking and choosing.” 27/9/2014

“The toxic thoughts in our minds become physical baggage in our brain, which literally cause brain damage.” 5/12/2014, 27/10/2014 and 7/10/2014
“Your mind will adjust your body’s biology and behaviour to fit with your beliefs.” 21/6/2014
“SID ROTH: But when you told me that we could change our genes I wish every doctor in the world would understand this cutting edge research because, you know, you go to a doctor and say your cholesterol was high, and they say, well, exercise, change your diet, but it could be your genes and there’s nothing you can do, so take this medicine that will have a zillion side effects. But you say, according to the latest brain research, if you follow what Jesus said you can change your genes. That’s just so amazing.
DR. LEAF: I know. It is phenomenal. If you think of it, it’s logical too, Sid …” Full transcript:

Dr Leaf draws her erroneous conclusions from the poor interpretation of poor evidence. For example, one of Dr Leaf’s favourite factoids is her statement that “Research shows that 75 to 98 percent of mental, physical and behavioral illness comes from one’s thought life.” [13: p33] Dr Leaf’s sources for this statement include, among others, an article that not only doesn’t mention the figure she attributes to it, but also directly contradicts her fundamental premise [14], and the misleading paraphrasing of an already dubious quote from a pseudoscientific author [15].

Dr Leaf also has a number of pet theories which betray her preference for pseudoscience, the main one being her assertion that the heart is actually a mini-brain that has dedicated cognitive functions. For example, in her books, she says,

“Your heart is in constant communication with your brain and the rest of your body, checking the accuracy and integrity of your thought life.   As you are about to make a decision, your heart pops in a quiet word of advice, well worth listening to, because when you listen to your heart, it secretes the ANF hormone that gives you a feeling of peace.” [12: p62, 13: p127]

Dr Leaf directly quotes the work of an organisation called HeartMath for her evidence that the heart acts as a mini-brain. Dr Leaf, via Heartmath, states that:
> The heart has a network of 40,000 neurons within it, called sensory neurites, which detect circulating hormones, neurochemicals, and sense heart rate and blood pressure,
> The heart secretes “neurotransmitters” and other hormones, which have an effect on the brain, such as atrial natriuretic factor, and oxytocin,
> The heart communicates with the brain and the rest of the body through neurological, biophysical, biochemical and “energetic” (ie: electromagnetic) means [16, 17].

HeartMath clarifies, “The heart’s brain is an intricate network of several types of neurons, neurotransmitters, proteins and support cells like those found in the brain proper. Its elaborate circuitry enables it to act independently of the cranial brain – to learn, remember, and even feel and sense.” [16]

So the “evidence” looks plausible on the surface, but absurd when considered in a broader biological context. For example, my heart may have 40,000 neurons, many of which are sensitive to circulating hormones, neurochemicals and which sense and feel, but then again, so does my rectum. Does my rectum have a mini-brain as well? Clearly not. The only brain you have is the one in your cranium. We do not think with our heart, our rectum, or any other body part.

A more in-depth rebuttal of Dr Leaf’s scientific claims can be found in my book: “Hold That Thought – Reappraising the work of Dr Caroline Leaf”, via Smashwords ( or iTunes (


The opening question from Dr Leaf’s presentation at the 2015 TEDx Oaks Christian School was, “Can the mind change the brain?”

Clearly the answer is: “No, it can not.”

Others are welcome to disagree, but in my humble opinion, I suggest that Dr Leaf is a pseudoscientist, and that her appearance on the TEDx stage is not based on scientific acumen, but on popularity and reputation, which in turn, is based on slick self-promotion and an availability cascade (a self-reinforcing process by which an idea gains plausibility through repetition).

Dr Leaf’s ideas may have popular approval, but TEDx is a vehicle for ideas worth spreading, not ideas that are popular. According to its guidelines, TEDx requests that pseudoscience be avoided, specifically stating, “TED and TEDx are platforms for showcasing and explaining genuine advances in science … Speakers should avoid the misuse of scientific language to make unsubstantiated claims.” (

Dr Leaf’s claims, that her research has significantly changed the lives of the students who were blessed to receive it, is simply not born out by any of her own published data – from her original case study through to her MMA project and her Switch On Your Brain program. Whatever the underlying reason … whether its hubris, naivety, or denial that’s driving her continued promotion of her own programs … her claims are baseless, and therefore an argument can be made that she breached the TEDx guidelines in presenting them, and indeed, she should never have been invited to deliver them from a TEDx stage in the first place.

The theme for the 2015 TEDx Oaks Christian School event was “Ridiculous”. I would argue that it was ridiculous that Dr Leaf promoted her research as life changing when in reality, it’s not much better than a placebo. It was ridiculous that Dr Leaf would share stories of the changes to the cognitive functioning of her patients from their brain damage and then claim that the brain does not influence the mind. It seems that Dr Leaf’s presentation certainly fitted their theme, although probably not in the way they intended. Lets hope for their sake that their “ridiculous” decision doesn’t effect their ability to host future TEDx presentations.

Of course, that’s just my opinion. What do you think, TEDx universe?


  1. Leaf, C.M., et al., Mind-Mapping approach (MMA): a culture and language” free” technique. The South African journal of communication disorders. Die Suid-Afrikaanse tydskrif vir Kommunikasieafwykings, 1993. 40: 35
  2. Leaf, C.M., The Mind Mapping Approach: a model and framework for geodesic learning, in Department of Communication Pathology, Faculty of Arts1997, University of Pretoria: Pretoria. p. 266.
  3. Leaf, C.M., et al., The development of a model for geodesic learning: the geodesic information processing model. The South African journal of communication disorders. Die Suid-Afrikaanse tydskrif vir Kommunikasieafwykings, 1997. 44: 53
  4. Eppler, M.J., A comparison between concept maps, mind maps, conceptual diagrams, and visual metaphors as complementary tools for knowledge construction and sharing. Information Visualization, 2006. 5(3): 202-10
  5. Farrand, P., et al., The efficacy of the `mind map’ study technique. Medical Education, 2002. 36(5): 426-31 doi: 10.1046/j.1365-2923.2002.01205.x
  6. Wickramasinghe, A., et al., Effectiveness of mind maps as a learning tool for medical students. South East Asian Journal of Medical Education, 2007. 1(1): 30-2
  7. D’Antoni, A.V., et al., Does the mind map learning strategy facilitate information retrieval and critical thinking in medical students? BMC Med Educ, 2010. 10: 61 doi: 10.1186/1472-6920-10-61
  8. Merchie, E. and Van Keer, H., Spontaneous Mind Map use and learning from texts: The role of instruction and student characteristics. Procedia – Social and Behavioral Sciences, 2012. 69: 1387-94
  9. Baars, B.J., Global workspace theory of consciousness: toward a cognitive neuroscience of human experience. Progress in brain research, 2005. 150: 45-53
  10. Baars, B.J. and Franklin, S., An architectural model of conscious and unconscious brain functions: Global Workspace Theory and IDA. Neural Netw, 2007. 20(9): 955-61 doi: 10.1016/j.neunet.2007.09.013
  11. Franklin, S., et al., Conceptual Commitments of the LIDA Model of Cognition. Journal of Artificial General Intelligence, 2013. 4(2): 1-22
  12. Leaf, C., Who Switched Off My Brain? Controlling toxic thoughts and emotions. 2nd ed. 2009, Inprov, Ltd, Southlake, TX, USA:
  13. Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:
  14. Cohen, S., et al., Psychological stress and disease. JAMA: the journal of the American Medical Association, 2007. 298(14): 1685-7
  15. Lipton, B.H., The biology of belief: Unleashing the power of consciousness, matter and miracles. 2008, Hay House, Inc:
  16. Rosch, P. Emotional balance and health. Science of The Heart: Exploring the Role of the Heart in Human Performance – An Overview of Research Conducted by the Institute of HeartMath 2013 [cited 2013, 16/7/2013]; Available from:
  17. Rosch, P. Head-Heart Interactions. Science of The Heart: Exploring the Role of the Heart in Human Performance – An Overview of Research Conducted by the Institute of HeartMath 2013 [cited 2013, October 20]; Available from:

Dr Caroline Leaf – Feed your children manure???

Screen Shot 2015-03-19 at 11.27.57 pm

I was entertained somewhat by Dr Leaf’s latest Facebook post this evening. In it, there was a pairing of water and a pot-plant, and sugary drinks and a child, with the words, “If you give this (water) to your plants? Why give this (sugary beverages) to your children.”

Without looking too closely, one might think that Dr Leaf was making a good point. Water is good, and sugar is bad, right?

With just a little more thinking, one can see that the metaphor is pretty weak. Plants aren’t children. Following the same logic of the metaphor, I should feed my children manure instead of food, since it’s clearly good enough for the pot-plant.

What is worrying about this post is Dr Leaf’s linking of diet with our Christian morals. Dr Leaf tries to link the concept of drinking water to the worship of God, because your body is a temple, and “Whether you eat or drink, or whatever you do, do it all for the glory of God.” (1 Corinthians 10:31). By logical extrapolation, Dr Leaf is therefore saying that drinking Coke is dishonouring God and the temple he gave for you. If you drink Coke, then you’re a bad Christian.

Though that’s really only Dr Leaf’s interpretation, because the scripture that she quotes isn’t talking about the composition of the food you eat but about it’s relationship to the sacrifice to idols. As far as I was aware, Coke isn’t used in any worship of idols before it’s bottled and distributed. So really, I don’t think whether you drink coke or other sodas will have any bearing on your relationship with God.

Perhaps Dr Leaf would have better spent her time outlining the studies that back up her overly dramatic statement “that sugary drinks like soda and processed orange juice can cause neurochemical havoc in your brain” rather than just hoping people will take her at her word.

Lets be real … no one in their right mind is encouraging children to have more sugar, mainly because of the excess calories, and not the hysterical notion of “neurochemical havoc”. Dr Leaf’s trying to get it right, but her poor metaphor, and the linking of ones diet to ones honouring of God probably went a step too far.

It would be nice if Dr Leaf could reexamine her knowledge of nutritional science and the scriptures that she uses so that she doesn’t weaken her credibility with such posts in the future.

The truth about ADHD

ADHD is always a popular topic … and an apoplexic topic. Any mention of ADHD seems to induce everyone within ear-shot to uncontrollably expectorate their half-baked opinion on the subject, like the Tourette’s syndrome of ignorance.

I’ve heard them all over the years …

ADHD is over diagnosed.
ADHD is just a label for bad parenting.
ADHD is caused by sugar.
ADHD is caused by food colouring / preservatives / gluten / (any other fad ‘toxin’)
ADHD is cured by diet / meditation / supplements / swiss balls.
ADHD medication (Ritalin) is overused / irresponsible / lazy parenting / harmful / ungodly.
ADHD doesn’t exist in France.
ADHD doesn’t exist at all.

I could go on, but if I do, I’m just going to get myself in a tizz.

ADHD is the new AIDS. There is so much misinformation and discrimination surrounding ADHD in our modern enlightened society that the stigma is worse than the actual illness, which really says something about how badly ADHD is treated in our communities.

One of the cruellest aspects of the cultural mismanagement of ADHD is the fact that it maligns the sufferers while simultaneously isolating them from much needed support. Saying that children with ADHD should just behave themselves, or parents of children with ADHD should just have better parenting skills is victim blaming at its worst.

In order to counter the prevalent ignorance of ADHD, even just a little, I want to give a crash course on the science so that at least somewhere on the searchable web, there is a counterbalance to the thousands of misinformed arm-chair ‘experts’ whose only experience with ADHD is reading the misguided perspectives of other so-called ‘experts’.

ADHD stands for Attention Deficit Hyperactivity Disorder.

The current formal definition that must be matched to have a diagnosis of ADHD is:

  1. Inattention: Six or more symptoms of inattention for children up to age 16, or five or more for adolescents 17 and older and adults; symptoms of inattention have been present for at least 6 months, and they are inappropriate for developmental level:
    * Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or with other activities.
    * Often has trouble holding attention on tasks or play activities.
    * Often does not seem to listen when spoken to directly.
    * Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., loses focus, side-tracked).
    * Often has trouble organizing tasks and activities.
    * Often avoids, dislikes, or is reluctant to do tasks that require mental effort over a long period of time (such as schoolwork or homework).
    * Often loses things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).
    * Is often easily distracted
    * Is often forgetful in daily activities.
  1. Hyperactivity and Impulsivity: Six or more symptoms of hyperactivity-impulsivity for children up to age 16, or five or more for adolescents 17 and older and adults; symptoms of hyperactivity-impulsivity have been present for at least 6 months to an extent that is disruptive and inappropriate for the person’s developmental level:
    * Often fidgets with or taps hands or feet, or squirms in seat.
    * Often leaves seat in situations when remaining seated is expected.
    * Often runs about or climbs in situations where it is not appropriate (adolescents or adults may be limited to feeling restless).
    * Often unable to play or take part in leisure activities quietly.
    * Is often “on the go” acting as if “driven by a motor”.
    * Often talks excessively.
    * Often blurts out an answer before a question has been completed.
    * Often has trouble waiting his/her turn.
    * Often interrupts or intrudes on others (e.g., butts into conversations or games)

In addition, the following conditions must be met:
- Several inattentive or hyperactive-impulsive symptoms were present before age 12 years.
- Several symptoms are present in two or more setting, (e.g., at home, school or work; with friends or relatives; in other activities).
- There is clear evidence that the symptoms interfere with, or reduce the quality of, social, school, or work functioning.
- The symptoms do not happen only during the course of schizophrenia or another psychotic disorder.
– The symptoms are not better explained by another mental disorder (e.g. Mood Disorder, Anxiety Disorder, Dissociative Disorder, or a Personality Disorder.


In Australia, ADHD cannot be formally diagnosed by anyone other than a paediatrician or a psychiatrist. So even as an experienced GP, I can’t officially diagnose it. The school counsellor or local naturopath can’t diagnose it. You can’t just pluck it out of the air. The diagnosis can only come from a medical specialist with at least a decade of university level training.

The official prevalence rate of ADHD (the number of people with a current diagnosis) is only 5%. According to some US based community surveys, nearly a half of those children are not on medication for it ( So much for Ritalin being overprescribed.

Stimulants vs nothing

ADHD is a predominantly genetic disorder which leads to specific structural deficiencies in the brain. Children with ADHD have a significant global reduction in the volume of grey matter, most prominently in a part of the brain called the right lentiform nucleus. These changes usually improve with age and improve with stimulant medication. There is also evidence of changes to the shape and size of other brain structures such as the amygdala and the thalamus (areas of the brain integral to sensory and emotional processing). Early evidence also exists which suggests changes in the white matter pathways connecting a number of critical brain regions. Studies investigating brain development have estimated that the frontal lobe development of ADHD children lags that of normal children by an average of about three years.

These changes in the brain are not caused by the child’s behaviour, since other studies have shown the same changes in the brains of unaffected first degree relatives (brothers or sisters), just to a milder degree.

Modern functional imaging techniques show that the brains of children with ADHD have abnormally low functioning in most of the brain structures related to attention and planning (numerous areas of the frontal cortex as well as the basal ganglia, thalamus and parietal cortices). At the same time, there is extra activity in portions of the brain related to the Default Mode Network (the day-dreaming part of your brain). So children with ADHD have brains in which the ‘day-dreaming’ network activity persists into, or emerges during, periods of task-related activity. This takes processing power away from the competing task-specific processing causing a deficit in performance. Studies show that Ritalin normalises this dysfunction.

The best evidence suggests that dopamine is the main neurotransmitter involved in ADHD. Other neurotransmitters are likely to be involved but the evidence is still being confirmed. Medications like Ritalin improve ADHD symptoms by increasing the amount of dopamine that the nerve cells have access to, improving the clarity of the signal between them.

Underlying all of these neural changes are genetics. While there have been no specific genes discovered in research thus far, twin studies have demonstrated a heritability of ADHD of up to 76%. The most significant environmental factors that are responsible for the remainder of the influence on ADHD are not nutritional factors such as sugar or food additives, but are low birth weight/prematurity and exposure to smoking during pregnancy.

Are there any better treatments for ADHD other than stimulants like Ritalin? Other non-stimulant medications are available although at this stage, Ritalin and Dexamphetamine still out-perform them. Cognitive therapies may mimic some of the brain changes of Ritalin but it is not clear whether the effectiveness of cognitive therapies are equal to or better than the stimulant medications. What is clear is that Ritalin doesn’t lead to a euphoric state (a “drug high”) when given orally. So children can not get addicted to Ritalin when used responsibly.

In summary, ADHD exists. It’s caused by the interaction of a number of genes and some environmental factors such as those related to prematurity, low birth weight and maternal smoking, which alter the growth and development of the brain, specifically the grey matter of the frontal cortex, the basal ganglia and thalamus, and the pathways which connect them. These structural changes cause the day-dreaming part of the brain to be more active and the attention and planning parts of the brain to be less active.

ADHD is not caused by food additives or sugar. There is no evidence that autoimmunity plays a significant part. Forcing your child to consume bone broth or stop eating gluten will not cure them.

ADHD is not caused by bad parenting. Ritalin is not evil. Medications like Ritalin and Dexamphetamine have been shown to improve the functioning of children with ADHD and improve their underlying neurological deficits.

It’s time to cut the crap. Our culture needs to stop victimising the child with ADHD and their parents, who already suffer enough from the ADHD without ignorant busy-bodies and self-titled experts chiming in and making their suffering even more pronounced. It’s time to stop judging those who choose the best for their child by medicating them, who do so in spite of the unfair and ill-informed criticism of everyone from their mother-in-law to the milkman when they do. It’s time to remove the stigma from one of the most common psychiatric disorders of childhood so that every child has an equal chance of growing into an adult that can realise their full potential.

That’s the truth about ADHD.


Cortese, S. (2012). The neurobiology and genetics of Attention Deficit/Hyperactivity Disorder (ADHD): what every clinician should know. Eur J Paediatr Neurol, 16(5), 422-433. doi: 10.1016/j.ejpn.2012.01.009

Gluten mad!

Tonight as I was browsing Facebook again, I came across an article a person had posted on gluten. The article claimed that gluten is connected to depression, and indeed, nearly every other neurological disorder for good measure.

Gluten is a protein found in certain grains like wheat, barley and rye. Gluten also makes foods taste better and improves their texture, so it’s often added to everything else.

The “gluten is toxic” meme is a very catchy one that’s doing the rounds again. I first heard of the idea that gluten is the cause of nearly every disease when I was in medical school, when every person I knew who’d seen a naturopath was told they had gluten intolerance and were conned into an unappetising and restrictive diet which didn’t make any of them better.

The same meme is now making it’s way back around again now that the low-fat, sugar-free, zucchini broth-type diet fads are waning.

The proposed link between depression, anxiety and gluten is a new twist to the old story. But with depression becoming a preeminent disease in the 21st century, the link doesn’t surprise me.

So what does the evidence say? Is gluten the culprit behind the modern scourge of mental illness?

I certainly don’t think so, at least according to my interpretation of the medical literature. As far back as 2001, researchers studying the mental health of patients with coeliac disease noted that coeliac disease patients had much higher levels of anxiety and depression than healthy matched controls (up to about three to six times greater in one study), and after a year on a gluten free diet, there were no changes to the rates of anxiety and depression (Addolorato et al., 2001).

In more recent times, larger studies have been performed. Hauser, Janke, Klump, Gregor, and Hinz (2010) confirmed higher levels of anxiety in German female coeliac patients who were on a gluten free diet, compared to the normal controlled population. Mazzone et al. (2011) showed that children with coeliac disease on gluten-free diets for about 7 years on average still showed an increased rate of anxiety and depression symptoms and showed higher scores in “harm avoidance” and “somatic complaints” as compared to healthy control subjects.

A larger cross sectional survey was performed in the Netherlands in 2013, on 2265 adults with coeliac disease (van Hees, Van der Does, & Giltay, 2013). That survey showed that a significantly higher proportion of those with coeliac disease, despite being on a strict gluten free diet, reporting a higher rate of anxiety and depression compared to the general population. It also showed (albeit in a smaller subgroup of respondents) that poor adherence with a gluten free diet did not affect the likelihood of depressive symptoms.

To be fair, cross sectional surveys and longitudinal cohorts aren’t necessarily the strongest form of evidence, but it is the best we’ve currently got. There was a recent randomised controlled trial, a stronger form of evidence, looking at the effect the introduction of gluten had on depressive symptoms in people who did not have coeliac disease but reported gluten sensitivity and were controlled on a gluten free diet (Peters, Biesiekierski, Yelland, Muir, & Gibson, 2014). While this showed some worsening of depressive symptoms in those subjects given gluten, the exposure was short, the effect was moderate, and the results should be considered cautiously given the small number of subjects reduced the power of the study.

Given the weight of evidence, I can’t help but be sceptical of books touting the ‘gluten = depression’ theory, books like “Grain Brain”. It’s author, American neurologist Dr David Perlmutter, attests that more than 38 different diseases are caused by gluten, including autism and depression. If you believe the celebrity chiropractor who reviewed Perlmutter’s work (, increased intestinal permeability and intestinal dysbiosis (“leaky gut” and bad gut bacteria) combine to increase inflammation in the blood and in the brain, causing depression.

But correlation does not equal causation. Just because brain diseases, inflammation and gut problems tend to occur together does not prove that gut problems cause inflammation and brain problems. Rather, the evidence suggests that it’s the other way around, with all of the processes linked to genetics.

For example, autism is related to a number of genes that both reduce the proteins that help nerve cells grow branches (Won, Mah, & Kim, 2013), and at the same time, switch on a low grade form of inflammation (Onore, Careaga, & Ashwood, 2012). I believe it’s the pre-existing inflammation that adds to the cellular dysfunction of the brain and at the same time, promoting low grade inflammation of a number of organs, including the gut. It’s the pre-existing inflammation that causes the gut to become “leaky”, not the “leaky” gut causing the inflammation.

Because if gluten was the primary cause, then why do people with coeliac disease who do not eat gluten report more depressive and anxious symptoms than control groups who do eat gluten? Why would those with coeliac disease who are eating sporadic gluten be just as depressed as those patients who do not?

If you don’t have coeliac disease, then gluten free diets are just like Amway products. You really don’t need them, and you could probably do much better without them. All you’re really doing is just making someone else obscenely rich.

Not only are you wasting your money, but you might also be harming your health by eating gluten free foods, since most foods that are stripped of gluten are also stripped of most of their other nutrients.

As Nash and Slutzky (2014) summarise, “Every major change in our diet carries with it the possibility of unforeseen risks. Many readers — the general public, as well as medical professionals — accept what they read at first glance. Myths have been part of our medical lore for millennia. Those jumping on the gluten-free/high-fat bandwagon may be disappointed when their symptoms are not mitigated; more critically, they may be at increased risk for other, more dangerous ailments.”

If you really think you feel better off gluten, then talk to your doctor or registered dietician to make sure you remain healthy off it.


Addolorato, G., Capristo, E., Ghittoni, G., Valeri, C., Masciana, R., Ancona, C., & Gasbarrini, G. (2001). Anxiety but not depression decreases in coeliac patients after one-year gluten-free diet: a longitudinal study. Scand J Gastroenterol, 36(5), 502-506.

Hauser, W., Janke, K. H., Klump, B., Gregor, M., & Hinz, A. (2010). Anxiety and depression in adult patients with celiac disease on a gluten-free diet. World J Gastroenterol, 16(22), 2780-2787.

Mazzone, L., Reale, L., Spina, M., Guarnera, M., Lionetti, E., Martorana, S., & Mazzone, D. (2011). Compliant gluten-free children with celiac disease: an evaluation of psychological distress. BMC Pediatr, 11, 46. doi: 10.1186/1471-2431-11-46

Nash, D. T., & Slutzky, A. R. (2014). Gluten sensitivity: new epidemic or new myth? Every major change in our diet carries with it the possibility of unforeseen risks. Am J Cardiol, 114(10), 1621-1622. doi: 10.1016/j.amjcard.2014.08.024

Onore, C., Careaga, M., & Ashwood, P. (2012). The role of immune dysfunction in the pathophysiology of autism. Brain Behav Immun, 26(3), 383-392. doi: 10.1016/j.bbi.2011.08.007

Peters, S. L., Biesiekierski, J. R., Yelland, G. W., Muir, J. G., & Gibson, P. R. (2014). Randomised clinical trial: gluten may cause depression in subjects with non-coeliac gluten sensitivity – an exploratory clinical study. Aliment Pharmacol Ther, 39(10), 1104-1112. doi: 10.1111/apt.12730

van Hees, N. J., Van der Does, W., & Giltay, E. J. (2013). Coeliac disease, diet adherence and depressive symptoms. J Psychosom Res, 74(2), 155-160. doi: 10.1016/j.jpsychores.2012.11.007

Won, H., Mah, W., & Kim, E. (2013). Autism spectrum disorder causes, mechanisms, and treatments: focus on neuronal synapses. Front Mol Neurosci, 6, 19. doi: 10.3389/fnmol.2013.00019

Dr Caroline Leaf – It’s no joke

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So, stop me if you’ve heard this one … This guy walks into a bar, and says, “Owww, that bar is really hard.”

Ok, that was a bad joke. Hey, I’m no Robin Williams. Some people have the knack of being able to make people laugh in almost any situation. I can get a few laughs, but I’m not a naturally gifted comic.

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. She isn’t a comedian either.

Her post today was a light-hearted dig at giant lizards with a taste for organic free-range humans, or perhaps the fact that most people know being “all organic, gluten free” should be left to the sanctimonious foodies of San Francisco.

The other part of her post wasn’t meant to be funny, but certainly contained a healthy dose of irony. In trying to justify her bit of light comic relief, she posted another of her subtly erroneous factoids, this time claiming that, “Laughing 100-200 times a day is equal to 10 minutes of rowing or jogging!”

Not according to real scientists, who have worked out that laughing is actually the metabolic equivalent to sitting still at rest, while jogging or rowing burns between 6 to 23 times as much energy, depending on how fast you run or row [1].

That would mean that I would have to laugh for at least a whole hour a day (or about 700 times based on the average chortle) to be even close to the energy burnt by a light jog.

On the grand scale of things, this meme probably doesn’t really matter. These sort of factoids are thrown around on social media all the time, and it won’t make a big difference to the health and wellbeing of most people. But it does help establish a pattern. Dr Leaf habitually publishes memes and factoids that clearly deviate from the scientific truth, proving that Dr Leaf has become a cross between a science fiction author and life coach, not a credible scientific expert. From her social media memes to her TV shows, all of her teaching becomes tainted as untrustworthy.

While today’s meme may not be so serious, if Dr Leaf can’t get her facts straight, pretty soon the joke will be on her.


  1. Ainsworth, B.E., et al., 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc, 2011. 43(8): 1575-81 doi: 10.1249/MSS.0b013e31821ece12

Fats and Figures: Re-examining saturated fat and what’s really good for your heart

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A Facebook friend forwarded me an article a few weeks back and asked for my humble medical opinion.

The article was entitled, “World Renowned Heart Surgeon Speaks Out On What Really Causes Heart Disease”. It was written by a man who said he was a heart surgeon, and who claimed to be coming clean on the real reason why our world has an epidemic of obesity and heart disease despite the low fat advice of the medical profession.

It’s a highly controversial topic right now. For decades, the western world was under the impression that fat was tobaccos right hand man in a war on good health. Standard medical dogma was that high cholesterol was bad, and that saturated fat was its main source. Evil butter was replaced with angelic margarine. Fatty red meat was always served with a generous side portion of guilt. Low fat became high fashion.

Today, the pendulum of public opinion has swung back with such amazing ferocity, it’s become more like a wrecking ball. Fat has returned to the fold as friend instead of foe. The once mighty cholesterol lowering medications called statins have become seen as another example of pharmaceutical company profits-before-patients. Sugar has become the new villain, and along with it, the nebulous concept of “inflammation” as the key mechanism of heart disease and strokes, and nearly every other medical ailment.

What started off as a three-paragraph reply on Facebook has evolved into a short eBook, which you can download for free from Smashwords (

In today’s post, I want to look at six things that, over the years, have been touted as contributing to or preventing heart disease, and see what the evidence says. The results may be surprising!

1. Is saturated fat bad? Is polyunsaturated fat good?

According to a meta-analysis of observational studies on dietary fats by Chowdhury et al. (2014), relative risks for coronary disease were 1.02 (95% CI, 0.97 to 1.07) for saturated fats, 0.99 (CI, 0.89 to 1.09) for monounsaturated, 0.93 (CI, 0.84 to 1.02) for long-chain n-3 polyunsaturated, 1.01 (CI, 0.96 to 1.07) for n-6 polyunsaturated, and 1.16 (CI, 1.06 to 1.27) for trans fatty acids. The total number of patients in all of the trials was more than half a million. This is pretty convincing evidence that saturated fats aren’t as bad as first believed.

What does all this mean? In statistical terms, a relative risk is the incidence of disease in one group compared to the incidence of disease in another. The risk of the disease in the two groups is the same if the relative risk = 1. A relative risk of 7.0 means that the experiment group has seven times the risk of a control group. A relative risk of 0.5 would mean the experiment group has half the risk of the control group. The confidence interval is a range of numbers in which there is a 95% chance that the true relative risk is in the interval. A result is “statistically significant” when the confidence interval (CI) does not cross the number 1.

So going back to the study by Chowdhury et al. (2014), only 2% more patients in the group with the highest saturated fat consumption had heart disease compared to the lowest saturated fat consumption. The confidence interval crossed 1, so that result may have been due to chance alone. For trans fatty acid consumption, 16% more people had heart disease in the higher consumption group compared to the lower consumption group, which was probably a real effect and not due to chance (the confidence interval did not cross 1). Simply put, trans-fats are bad. Saturated fats probably aren’t.

The same meta-analysis by Chowdhury et al. (2014) also reviewed supplementation with PUFA’s on the overall risk of heart disease. They found that in 27 randomised controlled trials with more than 100,000 people, relative risks for coronary disease were 0.97 (CI, 0.69 to 1.36) for alpha-linolenic acid supplements, 0.94 (CI, 0.86 to 1.03) for long-chain n-3 polyunsaturated acid supplements, and 0.89 (CI, 0.71 to 1.12) for n-6 polyunsaturated fatty acid supplements. In this case, there was a trend in favour of supplementation with omega-3 and omega-6 supplements, but it was small, and may have been due to chance. This is confirmed by other reviews (Rizos, Ntzani, Bika, Kostapanos, & Elisaf, 2012; Schwingshackl & Hoffmann, 2014)

So it appears that it doesn’t matter what fat you consume, saturated or polyunsaturated, or whether you supplement with fish oils or eat lots of fish, your cardiovascular risk is much the same. The only thing that’s definitely clear is that you should avoid trans-fats.

2. Is sugar bad for you?

That depends.

When we think of sugar, we think of sucrose, a carbohydrate made up of one glucose and one fructose molecule. There are many carbohydrates, which are just various combinations of different numbers of glucose/fructose molecules, sucrose being one type.

Sugar consumption is thought to be the modern scourge, it’s consumption linked to everything from cancer to gallstones. It’s been recently become the villain of cardiovascular disease as well. It’s thought to cause insulin resistance, inflammation and an increase in the fats circulating in the blood stream. So, is it as bad as they say? The evidence is surprising.

First of all, sugar doesn’t make you fat. Rather, it’s the calories you consume that make you fat. Te Morenga, Mallard, and Mann (2013) conclude their meta-analysis of dietary sugar and body weight, “Among free living people involving ad libitum diets, intake of free sugars or sugar sweetened beverages is a determinant of body weight. The change in body fatness that occurs with modifying intakes seems to be mediated via changes in energy intakes, since isoenergetic exchange of sugars with other carbohydrates was not associated with weight change.”

The intake of sugar and glucose don’t cause an increase in inflammation or cholesterol in healthy people. In a study on effects of sugar consumption on the biomarkers of healthy people, Jameel, Phang, Wood, and Garg (2014) found that consumption of sucrose and glucose actually decreased cholesterol. Fructose increased cholesterol, though interestingly, the Total:HDL ratio (which is prognostic for heart disease) did not change significantly with the consumption of any form of sugar. They also found that fructose was associated with an increase in inflammation, but glucose and sucrose reduced inflammation.

On the other hand, a study by Isordia-Salas et al. (2014) showed a small but significant association between those with high blood glucose level and inflammation, though they also found an association between inflammation and BMI (the body-mass index), so it’s not clear what the causal factor is.

There seems to be a clearer association between blood glucose after meals in those who have abnormal glucose metabolism. In patients with pre-diabetes, higher levels of blood glucose two hours after eating were associated with increased risk of death from cardiovascular disease and all causes (Coutinho, Gerstein, Wang, & Yusuf, 1999; Decode Study Group, 2003; Lind et al., 2014).

To melt your brain a little more, just because high glucose levels are associated with higher mortality doesn’t mean the lower the glucose, the better. In the study by the Decode Study Group (2003), low blood glucose had a higher mortality than normal glucose levels, and a meta-analysis by Noto, Goto, Tsujimoto, and Noda (2013) showed that low carbohydrate diets have a 30% increase in all-cause mortality.

How do you pull all of these seemingly contradictory studies together? The bottom line appears to be, according to the evidence so far, that consumption of sugar does not cause inflammation or significantly increase the risk of heart disease in healthy people who are able to metabolise it properly.

In those people who have abnormal glucose metabolism, the higher the glucose is after a meal (a measure of how well the body processes glucose), then the higher the risk is of inflammation, heart disease, and all-cause mortality.

The distinction between who has normal glucose metabolism and who has dysfunctional glucose metabolism is probably related to genetics. A study by Sousa, Lopes, Hueb, Krieger, and Pereira (2011) showed that genetic information was able to predict 5-year incidence of major cardiovascular events and overall mortality in non-diabetic individuals, even after adjustment for the persons blood sugar. Those without diabetes but who had a high genetic risk had a similar incidence of cardiovascular events compared to diabetics. So if you have the genes, your body doesn’t process the glucose properly and your risk is increased, even if you aren’t bad enough to have a diagnosis of diabetes.

Thus it appears that sugar is not the bad guy that everyone makes it out to be. Excess sugar will make you fat, but so will excess everything-else. It probably won’t kill you unless you’re genetically pre-disposed to handle it poorly. And there’s the rub, because we don’t have the capacity to test for that clinically yet.

So the last word on sugar is that it’s a sometimes food. You may be lucky enough to handle large amounts of sugar, but the best advice at this time is don’t tempt fate by eating large quantities of it.

3. Is obesity bad for you?

Again, that depends.

It used to be thought that obesity posed a linear risk, that is, the fatter you were the higher your risk of heart attacks, cancer, diabetes, everything. Then in 2013, a meta-analysis by Flegal, Kit, Orpana, and Graubard (2013) showed that people who were overweight (but not obese) had better survival than those who were normal weight.

Later in 2013, Kramer, Zinman, and Retnakaran (2013) published a meta-analysis which showed that metabolically unhealthy people of normal BMI were at greater risk of cardiovascular disease than metabolically healthy obese people.

Last year a paper by Barry et al. (2014) showed that those who were unfit were twice as likely to die compared to people who were fit, irrespective of their BMI.

So obesity doesn’t seem to be the problem after all, rather it’s a persons ability to handle blood sugar, cholesterol and blood pressure that’s the problem. It seems that more people with obesity have these metabolic problems, but correlation does not equal causation. There’s probably a undetermined factor that links obesity and metabolic dysfunction.

I’m not suggesting that we should all get fatter. Obesity has problems of its own, unrelated to metabolic issues, that make it problematic. We should still be careful about our weight. The take-home message is that skinny does not necessarily mean healthy and that focusing on what the scales are saying may be distracting us from the real problem.

4. Is meat bad for you? Should we be vegetarians?

In a word, no.

In the two available meta-analyses of the studies on red meat consumption (Larsson & Orsini, 2014), and red meat vs white meat vs all meat (Abete, Romaguera, Vieira, Lopez de Munain, & Norat, 2014), there was a statistical but moderate increase in death and heart disease from processed meats.

There was a trend towards a higher death rate in those who ate the most red meat, but the trend wasn’t statistically significant (i.e.: may have been related to chance). There was no trend associated with white meat consumption. So it appears that as long as it’s not processed meat, red meat isn’t as bad as people first thought.

Meat might not be particularly bad, but are vegetarian diets better? Again, probably not. The meta-analysis by Huang et al. (2012) shows that there’s a positive trend for vegetarian diets, though again, that might be attributable to chance as the results are not statistically significant.

The take-away message? Even though the trends may be related to chance, the trend is favourable for vegetables and not as favourable for red meat. So eat more veggies, eat less red meat, but don’t let some sanctimonious vegan convince you that meat is noxious and vile.

5. Is alcohol good for you?

A different meme recently came around my Facebook feed, entitled, “Is Drinking Wine Better Than Going To The Gym? According To Scientists, Yes!” For a while there, I had fantasies about giving my membership card back to the gym and heading down to the local bottle shop for my daily workout instead.

Disappointingly, it turns out that red wine isn’t better than exercise according to the research that I uncovered. However, my research did suggest that the daily exercise of wine drinking is still beneficial, and not just red wine, but alcohol of any form. Ronksley, Brien, Turner, Mukamal, and Ghali (2011) showed about two standard drinks of alcohol daily conferred a 25% reduction in deaths from heart disease (relative risk 0.75 (0.68 to 0.81)), and a small but statistically strong reduction in death from all causes of 13% (relative risk 0.87 (0.83 to 0.92)). The risk reduction of coronary heart disease from alcohol was also confirmed in a more recent study by Roerecke and Rehm (2014), who showed that death from heart disease was reduced by 36% for those who consistently consumed less than three standard drinks a day (relative risk 0.64 (0.53 to 0.71)).

The effect applies to consistent daily consumption, not to drinking in a cluster pattern (binging or weekend-drinking only, for example). And there’s a gender difference, women having the maximum beneficial effect at about one drink a day, and two drinks a day in men.

6. Is exercise good for you?

In a word, yes!

I’ve never seen a study that showed exercise was harmful. Exercise improves overall metabolism, decreases cardiovascular disease, improves mood and memory and increases your lifespan, amongst many other things. If exercise came in pill form, it would be labelled a wonder-drug.

As discussed earlier, fit people have a better rate of survival compared to unfit people, whether they’re obese or not (Barry et al., 2014). And the key to fitness is exercise. In a large meta-analysis by Samitz, Egger, and Zwahlen (2011), 80 studies involving more than 1.3 million subjects in total were analysed, showing that the highest levels of exercise had an all cause mortality reduction of 35% (relative risk 0.65 (0.6 to 0.71)).

There’s always debate about what form of exercise is best. Are you better to do weights, do interval training, or run for hours? Honestly, it probably doesn’t matter that much in the end. What is important is that you work hard enough to elevate your heart rate and break a sweat. If you aren’t very fit, it won’t take much exercise to do that. If you are very fit, it probably will. But for the average person, you don’t have to jump straight into a boot camp style program and work so hard that you’re puking everywhere, and so sore afterwards that you can’t move for a week. Common sense prevails!


Abete, I., Romaguera, D., Vieira, A. R., Lopez de Munain, A., & Norat, T. (2014). Association between total, processed, red and white meat consumption and all-cause, CVD and IHD mortality: a meta-analysis of cohort studies. Br J Nutr, 112(5), 762-775. doi: 10.1017/S000711451400124X

Barry, V. W., Baruth, M., Beets, M. W., Durstine, J. L., Liu, J., & Blair, S. N. (2014). Fitness vs. fatness on all-cause mortality: a meta-analysis. Prog Cardiovasc Dis, 56(4), 382-390. doi: 10.1016/j.pcad.2013.09.002

Chowdhury, R., Warnakula, S., Kunutsor, S., Crowe, F., Ward, H. A., Johnson, L., . . . Di Angelantonio, E. (2014). Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Ann Intern Med, 160(6), 398-406. doi: 10.7326/M13-1788

Coutinho, M., Gerstein, H. C., Wang, Y., & Yusuf, S. (1999). The relationship between glucose and incident cardiovascular events. A metaregression analysis of published data from 20 studies of 95,783 individuals followed for 12.4 years. Diabetes Care, 22(2), 233-240.

Decode Study Group, E. D. E. G. (2003). Is the current definition for diabetes relevant to mortality risk from all causes and cardiovascular and noncardiovascular diseases? Diabetes Care, 26(3), 688-696.

Flegal, K. M., Kit, B. K., Orpana, H., & Graubard, B. I. (2013). Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis. JAMA, 309(1), 71-82. doi: 10.1001/jama.2012.113905

Huang, T., Yang, B., Zheng, J., Li, G., Wahlqvist, M. L., & Li, D. (2012). Cardiovascular disease mortality and cancer incidence in vegetarians: a meta-analysis and systematic review. Ann Nutr Metab, 60(4), 233-240. doi: 10.1159/000337301

Isordia-Salas, I., Galvan-Plata, M. E., Leanos-Miranda, A., Aguilar-Sosa, E., Anaya-Gomez, F., Majluf-Cruz, A., & Santiago-German, D. (2014). Proinflammatory and prothrombotic state in subjects with different glucose tolerance status before cardiovascular disease. J Diabetes Res, 2014, 631902. doi: 10.1155/2014/631902

Jameel, F., Phang, M., Wood, L. G., & Garg, M. L. (2014). Acute effects of feeding fructose, glucose and sucrose on blood lipid levels and systemic inflammation. Lipids Health Dis, 13(1), 195. doi: 10.1186/1476-511X-13-195

Kramer, C. K., Zinman, B., & Retnakaran, R. (2013). Are metabolically healthy overweight and obesity benign conditions?: A systematic review and meta-analysis. Ann Intern Med, 159(11), 758-769. doi: 10.7326/0003-4819-159-11-201312030-00008

Larsson, S. C., & Orsini, N. (2014). Red meat and processed meat consumption and all-cause mortality: a meta-analysis. Am J Epidemiol, 179(3), 282-289. doi: 10.1093/aje/kwt261

Lind, M., Tuomilehto, J., Uusitupa, M., Nerman, O., Eriksson, J., Ilanne-Parikka, P., . . . Lindstrom, J. (2014). The association between HbA1c, fasting glucose, 1-hour glucose and 2-hour glucose during an oral glucose tolerance test and cardiovascular disease in individuals with elevated risk for diabetes. PLoS One, 9(10), e109506. doi: 10.1371/journal.pone.0109506

Noto, H., Goto, A., Tsujimoto, T., & Noda, M. (2013). Low-carbohydrate diets and all-cause mortality: a systematic review and meta-analysis of observational studies. PLoS One, 8(1), e55030. doi: 10.1371/journal.pone.0055030

Rizos, E. C., Ntzani, E. E., Bika, E., Kostapanos, M. S., & Elisaf, M. S. (2012). Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. JAMA, 308(10), 1024-1033. doi: 10.1001/2012.jama.11374

Roerecke, M., & Rehm, J. (2014). Alcohol consumption, drinking patterns, and ischemic heart disease: a narrative review of meta-analyses and a systematic review and meta-analysis of the impact of heavy drinking occasions on risk for moderate drinkers. BMC Med, 12(1), 182. doi: 10.1186/s12916-014-0182-6

Ronksley, P. E., Brien, S. E., Turner, B. J., Mukamal, K. J., & Ghali, W. A. (2011). Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. BMJ, 342, d671. doi: 10.1136/bmj.d671

Samitz, G., Egger, M., & Zwahlen, M. (2011). Domains of physical activity and all-cause mortality: systematic review and dose-response meta-analysis of cohort studies. Int J Epidemiol, 40(5), 1382-1400. doi: 10.1093/ije/dyr112

Schwingshackl, L., & Hoffmann, G. (2014). Dietary fatty acids in the secondary prevention of coronary heart disease: a systematic review, meta-analysis and meta-regression. BMJ Open, 4(4), e004487. doi: 10.1136/bmjopen-2013-004487

Sousa, A. G., Lopes, N. H., Hueb, W. A., Krieger, J. E., & Pereira, A. C. (2011). Genetic variants of diabetes risk and incident cardiovascular events in chronic coronary artery disease. PLoS One, 6(1), e16341. doi: 10.1371/journal.pone.0016341

Te Morenga, L., Mallard, S., & Mann, J. (2013). Dietary sugars and body weight: systematic review and meta-analyses of randomised controlled trials and cohort studies. BMJ, 346, e7492. doi: 10.1136/bmj.e7492

Dr Caroline Leaf and dualism revisited

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Are we a body with a mind, or a mind with a body?

This may sound like a chicken-and-egg type of conundrum, but it’s a deep philosophical question. The concept of the separation of the mind from the body is known as dualism, and has been debated for centuries because the answer to that question then guides a lot of other philosophies and theories.

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. She believes that the body and brain are separate from the mind, which significantly influences her teaching. Take, for example, her social media meme-of-the-day today. She posted that, “The brain does not change itself… our MIND changes the brain”. If one assumes that the mind is separate from our brain, then its plausible that the mind influences the brain.

Except that it doesn’t. Our mind is a product of our brain, not a separate entity. Neurological damage from injuries or tumours, electrical stimulation of the brain in the lab, the effect of illicit drugs on the brain like LSD or marijuana, and everyday examples like the changes to our thinking under the influence of caffeine or alcohol, all prove that changes to the structure and function of the brain change thought patterns. It isn’t the other way around. Every brain changes itself too – the brain of an embryo or foetus undergoes massive changes but foetuses don’t have streams of conscious thought. Dr Leaf’s meme is scientifically misguided.

Perhaps what is more worrying is Dr Leaf’s use of scripture to try and justify her view that the mind and the brain are separate. To introduce her meme, Dr Leaf wrote, “Read Luke 16:19-31 to see that the mind is separate from the brain – this is God’s divine design.”

There are a number of scriptures that theologians use to discuss the biblical basis for the separation of the body and soul, but Luke 16:19-31 isn’t one of them. That passage is the parable of Lazarus and the rich man.

It says:

‘There was a rich man who was dressed in purple and fine linen and lived in luxury every day. At his gate was laid a beggar named Lazarus, covered with sores and longing to eat what fell from the rich man’s table. Even the dogs came and licked his sores.
‘The time came when the beggar died and the angels carried him to Abraham’s side. The rich man also died and was buried. In Hades, where he was in torment, he looked up and saw Abraham far away, with Lazarus by his side. So he called to him, “Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.”
‘But Abraham replied, “Son, remember that in your lifetime you received your good things, while Lazarus received bad things, but now he is comforted here and you are in agony. And besides all this, between us and you a great chasm has been set in place, so that those who want to go from here to you cannot, nor can anyone cross over from there to us.”
‘He answered, “Then I beg you, father, send Lazarus to my family, for I have five brothers. Let him warn them, so that they will not also come to this place of torment.”
‘Abraham replied, “They have Moses and the Prophets; let them listen to them.”
‘“No, father Abraham,” he said, “but if someone from the dead goes to them, they will repent.”
‘He said to him, “If they do not listen to Moses and the Prophets, they will not be convinced even if someone rises from the dead.”’ (Luke 16:19-31, NIV)

I’m not sure exactly where the convincing proof of the separation of our mind and our body is found in this passage. This is a description of the afterlife, and in this parable, the rich man was very specific about memories (“I have five brothers …”) as well as physical sensations (“I am in agony in this fire”) and even parts of the body (Lazarus’s finger, his tongue). Jesus isn’t telling a story of how the mind is separate to the body, but of a different dimension in which the body and the mind are still together. This passage isn’t proof for the concept of dualism, but against it.

Dualism also has a number of fatal scientific and philosophical flaws, in particular that dualism is conceptually fuzzy, experimentally irrefutable, considers only the adult mind, and violates physics, in particular the law of conservation of energy.

So Dr Leaf bases her teaching on a scientifically and philosophically untenable concept and then attempts to use a scripture which refutes dualism in her attempt to support it. That’s audacious, but then to claim that it’s God’s divine design is, at best, a little brazen.

Dualism may be one of her fundamental philosophies, but I think Dr Leaf should review the basis for it, and possibly reconsider her reliance on it.

For a more in-depth discussion on Dr Leaf and dualism, please see my essay: Dr Caroline Leaf, Dualism, and the Triune Being Hypothesis