Lancet confirms fat is bad

Earlier this week, the prestigious medical journal The Lancet published an article about the health effects of obesity [1].

Spoiler alert – obesity kills you.

That sounds a lot like old news.  Why is a leading medical journal wasting space printing studies that tell us what we already know?  Well, up until now, the answer wasn’t as settled as people might have thought.

From the earliest writings of the ancient Greeks, fat people were always considered weak-willed or morally lacking.  Obese people either over-indulged or were lazy sods that deserved the indignation of the clearly morally superior skinny people.  Medical science initially seemed to back up that notion with hard data.  Body Mass Index (or BMI, your weight in kilograms divided by your height in metres squared) between 20 and 25 was the ultimate goal, and if you were above that, you were set to live a shorter and unhappier life.

Then a few years ago, a few studies came out showing that being overweight wasn’t as dire as people thought, and in fact, some studies showed that being overweight and mildly obese offered a small survival advantage over a weight in the “normal” range [2].  This was known as the obesity paradox.

So questions hung in the air like the sickly sweet smell of freshly baked donuts – Did the medical community get obesity wrong?  Were we meant to be cuddly instead of bony?  Were the lard nazi’s tricking us into lifestyles of kale and sit ups under false pretences?

The study by the objectively named Global BMI Mortality Collaboration seems to have definitively answered those questions.  The Global BMI Mortality Collaboration was a collective effort of more than 500 researchers from more than 32 countries, who pooled the resources of 239 different studies involving more than 10 million adults.  The collaborators weeded out more than 6 million people to form a group of 3,951,455 people who had never smoked and had not been diagnosed with a chronic disease before being recruited, and who had survived for more than 5 years after being recruited.  This made their group of participants in this study as statistically robust as possible.  These participants were followed for about 14 years.  Overall, 385,879 of them died.  To see whether obesity had an impact on mortality, they adjusted the raw numbers for age and gender, and calculated the likelihood of a participant dying depending in their BMI.

It isn’t good news for those of us who are of ample proportion.  Compared to those in the healthiest weight range, the most obese had a two-and-half times greater risk of dying from any cause.  Those who were overweight but not obese, which the previous studies suggested may have been ok, had an increased risk of dying too, but only by about 7%.  Obese males had a higher risk of dying than obese females, and obesity was worse for you if you were obese and young rather than obese and old.  Though before all the skinny people start skiting, those with a BMI of under 20 also had a higher mortality.  The best place to be was with a BMI of 20-25.


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Statistically speaking, this is a really strong study, so the conclusions it draws are hard to argue with.  It confirms that the BMI of 20-25 is the ideal weight, and that either extreme of body weight is certainly undesirable.

There are a couple of things to note.  Firstly, being overweight still isn’t that bad.  Sure, it’s not ideal like the older studies may have said, but a 7% increase in all-cause mortality isn’t going to particularly cut your life short.  So don’t panic about your love handles just yet.

Secondly, despite the statistical power of this study, it really only answers the single question: Is obesity related to mortality?  It answers it, and it answers it conclusively, but it doesn’t tell us how or why obesity and mortality are related, which are more important questions overall.

Because while it’s necessary to know that obesity, illness and death are related, knowing how they are related can then help us understand the why of obesity, which will then help doctors give patients real information that they can use.

For example, the Lancet study didn’t look at causation.  Is it that obesity causes chronic diseases which then cause early mortality like is the case with smoking?  Or is it that there’s another cause underlying both obesity and chronic disease, with obesity being unfairly framed in a guilt-by-association way?

Obesity Guilty Framed

What about mitigating factors?  If you’re fat but you’re also very fit, what’s your mortality then?  If you have a gastric bypass or a gastric sleeve and you shed a hundred pounds, does your mortality improve?  I’ll try and answer some of these question in future blogs.

Like all good research, this study in The Lancet seems to have generated more questions than answers.  What’s certain is that more research needs to be done.

If you are obese and you are concerned about your health, then talk to your GP or dietician.  Be sensible with your health.  Sure, obesity isn’t great, but you can sometimes do as much damage to yourself through poorly designed weight loss programs than you can with a dozen donuts.

[1]        Global BMI Mortality Collaboration. Body-mass index and all-cause mortality: individual participant data meta-analysis of 239 prospective studies in four continents. Lancet 2016 13 july 2016.
[2]        Flegal KM, Kit BK, Orpana H, Graubard BI. Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis. JAMA : the journal of the American Medical Association 2013 Jan 2;309(1):71-82.

Does helping others help you?

John Holmes wrote “There is no exercise better for the heart than reaching down and lifting people up.”

We all know that exercise is good for us, but is the exercise of the heart, “reaching down and lifting people up” just as good for us?

Dr Caroline Leaf is a communication pathologist and self-titled cognitive neuroscientist.  Her meme of the day today was a claim that “Helping others can increase your lifespan.”  She explained that “Researchers found a link between serving others, improved health and decreased mortality! See more at:”.

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The journal she referenced was a 2013 article by Poulin et al in the American Journal of Public Health [1].  Poulin and his colleagues examined data from nearly 850 people in the Detroit area.  At the start of their study, they asked their participants about stressful life events in the last year and whether they provided tangible assistance to friends or family members.  They then followed their participants for five years and analysed the characteristics of who died in that time.

According to the study by Poulin, those who helped others were younger, healthier, more likely to be White, of higher socioeconomic status, and higher in social support and social contact than those who didn’t help, all factors that have been shown to influence mortality.  They also noted that 70% of their cohort didn’t experience any stressful life events.  While they adjusted for these variables, their statistics would still be affected by them.  As it turns out, while their results were significant, their numbers had broad confidence intervals, so the effect they found is very weak.

What about other studies looking at the same question but in a different way?  Well, there are mixed findings.  Roth and colleagues published a study in 2013 in the American Journal of Epidemiology which also showed that care-givers had better life expectancy than matched controls [1] but then a number of other studies show the opposite.  The Caregiver Health Effects Study found that those who were providing care to a disabled spouse and who reported some strain associated with that care had a 63% elevated risk of death compared with non-caregiving spouses [2]. Other studies suggest that caregivers have poorer mental and physical health status than non-caregivers [3], and caregiving has been widely portrayed as a serious public health problem in the professional literature [4, 5].

So while Poulin found a loose association between helping others and decreased mortality, Dr Leaf has taken that a step too far:

> Firstly, correlation does not equal causation.  Just because a study found those who helped others had a decreased mortality doesn’t mean that the reverse, helping others increases your lifespan, necessarily holds.  There may be other explanations.
> Secondly, other studies show conflicting results, so Poulin’s study may be a statistical hiccough.

It’s not clear that helping others is actually good for our health.  That doesn’t mean to say we shouldn’t help others. I think we should, if for no other reason than the golden rule, “Do unto others as you would have them do unto you.”  But we can’t definitively say that helping others will help us directly by making us live longer.  That’s scientifically still up in the air.


[1]        Poulin MJ, Brown SL, Dillard AJ, Smith DM. Giving to others and the association between stress and mortality. Am J Public Health 2013 Sep;103(9):1649-55.
[2]        Schulz R, Beach SR. Caregiving as a risk factor for mortality: the Caregiver Health Effects Study. JAMA : the journal of the American Medical Association 1999 Dec 15;282(23):2215-9.
[3]        Pinquart M, Sorensen S. Differences between caregivers and noncaregivers in psychological health and physical health: a meta-analysis. Psychol Aging 2003 Jun;18(2):250-67.
[4]        Talley RC, Crews JE. Framing the public health of caregiving. Am J Public Health 2007 Feb;97(2):224-8.
[5]        Centre for Disease Control and Prevention. Caregiving, A Public Health Priority.  2010, 7 Dec 2010 [cited 2016 Jan 16]; Available from:

Drink up or work out? Is alcohol really better than exercise?


An article came through my Facebook feed today which grabbed my attention. Entitled, “Is Drinking Wine Better Than Going To The Gym? According To Scientists, Yes!“, the article suggested that red wine with it’s particular blend of anti-oxidants was in fact proven by scientists to be more beneficial to you than slogging it out at the gym.

I tend to prefer drinking red wine to going to the gym, as do a lot of other people it seems, given the viral-esque proliferation of this article through social media. If it were true that red wine was equivalent to exercise then I needed to rescind my newly acquired gym membership and swap it for a wine club membership post-haste. If it were true …

Even though my aching legs wanted it to be true, my sceptical brain held sway. I needed to find the answer to this vital question. If it were true, it would be a good excuse to enjoy a glass of red on a more regular basis. I could even come up with my own little euphemism for it … yes … I would call it “my daily workout”! My thighs would be much happier.

I took a deep breath and started to have a look through the published medical literature, looking to see if there were large studies or meta-analyses on red wine, exercise and all cause mortality. Interestingly there were a few studies on red wine, but mostly looking at its anti-oxidant effects, and not on the overall health benefit. However, there were a number of papers on the effects of alcohol consumption more broadly and its effect on heart disease and deaths from any cause. The study by 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 (95% Confidence Interval 0.68 to 0.81)).  The study also showed a small but statistically strong reduction in all-cause mortality 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)). So far so good … “my daily workout” was looking promising.

What about exercise? Well, a meta-analysis by Samitz, Egger, and Zwahlen (2011) analysed 80 studies involving more than 1.3 million subjects in total, and found that the highest levels of exercise had an all cause mortality reduction of 35% (relative risk 0.65 (0.6 to 0.71)). Damn! 35% beats 13% … I couldn’t give up in the gym just yet. I could feel my legs silently groaning.

In fairness, the article by Samitz and colleagues found that 150 minutes per week of moderate to vigorous exercise a week had a relative risk of mortality of 0.86 (0.8 to 0.92), so that’s comparable to the benefit conferred by 2 standard drinks a day in the study by Ronksley et al. Strictly speaking, the numbers aren’t directly analogous as each study is limited by the vagaries of the statistics they pooled. Red wine isn’t better than going to the gym as the Facebook article suggested, but they are probably comparable.

So, what to do with this information? I’ve decided that I need to adopt two daily workouts. Two standard drinks of alcohol a day is more than likely going to reduce my mortality, as will 25-30 minutes or more a day of moderate intensity exercise. I’m not exactly sure what the combined effect of both workouts will be on my longevity, but I’m pretty sure it won’t make things worse.



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

One note of caution: Roerecke and Rehm (2014) note that the relative risk from alcohol is a J-shaped curve. More than three standard drinks a day increases the risk from alcohol, especially for women, which is in keeping with the Australian national guidelines for alcohol consumption (

If you’re concerned about your drinking and you want help, talk to your local GP, local community health service, call the alcohol helpline in your state (for Australian state-based helplines, see or visit the DrinkWise website

Fat checking … sorry, fact checking

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As I was living vicariously on Facebook again this afternoon, I came across a forwarded page from nutritionist Christine Cronau. She was previewing tonight’s (Australian) ABC episode of Catalyst, on the topic of the low fat diet.

It’s not that she or the ABC are necessarily wrong about low fat diets. Some scientists have been sceptical of the evidence for low fat diets every since they were proposed in the late 1970’s [1]. Often, low fat foods have been manufactured with extra sugar to make them palatable again [2]. So while western consumers have been thinking they’ve been doing the right thing, they’ve probably been making the problem worse.

We’re also a society of carnivores, and the meat consumed in modern society is much higher in saturated fat. Plant and seafood based diets contain a high number of poly-unsaturated fatty acids (omega-3 and omega-6) which has also been a recommendation for our heart health, however a study in JAMA in 2012 suggested that high levels of omega-3 PUFAs did not protect from cardiovascular disease or reduce all cause mortality [3]. On the other hand, it appears that reviews of scientific research have suggested that saturated fat doesn’t pose a significant risk for cardiovascular disease or all-cause mortality either [4].

So it’s true that we may have to review exactly why plant based diets are good for us. What I raised an eyebrow at was her suggestion that, “What in the world did we do before cholesterol-lowering meds? Oh, that’s right, before we started mass producing sugar and back when we enjoyed plenty of saturated fat, heart disease was pretty much non-existent.”

This is a classic case of “two wrongs don’t make a right”. Sure, low fat diets are probably not the all-glorious panacea that they were touted to be, but suggesting that heart disease didn’t exist before the rise of sugar and low fat foods is grossly inaccurate. A quick glance at the data of the Australian Bureau of Statistics shows that heart disease peaked in the late 1960’s, which was coincidentally before we started mass producing sugar and back when we enjoyed plenty of saturated fat, and has since dropped significantly.

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Is that because of dietary guidelines recommending a low fat diet? There are many contributors to heart disease, so low fat diets can’t be singled out as the sole cause, especially in light of the reviews I discussed above. The reduction of smoking may be part of it, as smoking has dropped in the same amount of time, although a significant proportion of our population still smoke.

Whatever the reason, it isn’t a good reflection when you try and support your argument against a fallacy with a fallacy of your own. I haven’t read any of her other material, so her books maybe quite cogent. However, Ms Cronau’s Facebook post today provides a good example of how cognitive biases can sometimes blind us to facts that don’t agree with our chosen position, and why we all need to be careful when evaluating the evidence of “experts” on line.


  1. La Berge, A.F., How the ideology of low fat conquered america. J Hist Med Allied Sci, 2008. 63(2): 139-77 doi: 10.1093/jhmas/jrn001
  2. Malnick, E., et al. Low fat foods stuffed with ‘harmful’ levels of sugar. The Telegraph, 2014.
  3. Rizos, E.C., et al., Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. JAMA, 2012. 308(10): 1024-33 doi: 10.1001/2012.jama.11374
  4. Hoenselaar, R., Saturated fat and cardiovascular disease: the discrepancy between the scientific literature and dietary advice. Nutrition, 2012. 28(2): 118-23 doi: 10.1016/j.nut.2011.08.017