Comment: Why being ‘overweight’ means you live longer: the way scientists twist the facts.

OK, so a friend of mine recently posted a link on Facebook to an article entitled ‘Why being ‘overweight’ means you live longer: the way scientists twist the facts’. I can’t lie, just the title alone made my blood boil. My main concern was, aside from what appeared to be an oversimplification of a phenomenon that scientists know as the ‘obesity paradox’, the title also plays beautifully into the ‘us vs them’ notion that academics are somehow untrustworthy. But, after my blood pressure settled, I decided to give it the benefit of the doubt and read the whole article – I’ve heard at numerous ‘media training’ workshops that it’s not uncommon for editors to alter article titles just before print to make them more appealing and more likely to garner views, so perhaps the body of the article was a bit more nuanced?

The article overall gave the impression that the author was well versed in scientific literature, using well placed quotes from research papers to highlight important points. For example, the author quotes a study from 2005 which used medical data (collected between 1971 and 1994) to show increased mortality (risk of death) in those with BMI’s (Body Mass Index) over 30 (i.e. those classified as obese). He correctly points out that the title of this paper (‘Excess deaths associated with underweight, overweight and obesity’) is misleading and implies that being overweight (i.e. having a BMI of between 25 and 30) increases your risk of mortality, when the study actually finds lower mortality in those with BMI’s between 25 and 30 than for individuals in the ‘ideal’ BMI range (18.5-25), I.e. being moderately overweight is good for you.

These findings do actually agree with a number of similar studies. In fact, in addition to these findings, there are also a whole host of studies which suggest that being overweight can lead to better survival rates following a large range of medical conditions (for example coronary heart disease, chronic heart failure, stroke and more).

So, do I agree with this article? Well, partially.

I agree that the obesity paradox exists and these findings are not often spoken about. However, the reason that they are not often publicised is not because academics want to ‘twist the facts’ or, as the author states, that ‘no one can bring themselves to say: Sorry, we were wrong. A BMI between 25 and 29 is the healthiest weight of all. For those of you between 20 and 25, I say, eat more, become healthier’. It’s because there is much more to these findings than first meets the eye.

I don’t think many doctors or researchers would argue that obesity, especially weight carried around the stomach, is a major risk factor for type 2 diabetes, lipid disorders, hypertension, coronary heart disease and some cancers. A quick search of Google Scholar will turn up a stack of articles suggesting that increased weight is linked to a whole range of long-term conditions.

But, how can both these findings be correct? How can it be possible that being overweight can mean you live longer but you are also more likely to suffer from a chronic illness (i.e. diabetes or heart disease)?

I believe that this is the question we are yet to find a satisfactory answer to, and therefore the reason it’s best to be cautious about making statements such as “being “overweight” is the healthiest and most “normal” weight of all”.

A paper entitled ‘The Obesity Paradox Does Exist’ expressed this problem very well, stating: “the discussion over the existence of the obesity paradox cannot lead to an underestimation of obesity as a crucial risk factor for the development of cardiovascular and metabolic diseases that requires comprehensive prevention and management strategies”.

But what’s my overall impression of this article?

I believe that it does raise awareness of a medical phenomenon which needs to be discussed but, that it does so in a dangerous and inflammatory way. Blaming scientists and accusing them of manipulating/twisting results is not helpful. Neither is writing a biased article which does not acknowledge the breadth and depth of understanding around a topic – i.e. it’s just as dangerous to tell individuals that it’s entirely healthy to be overweight (in the case of this article to even go as far as to suggest that the dangers of obesity are greatly overrated) as it is to ignore this obesity paradox entirely and blame everything on excessive weight. We need to be smart and realise that any reference to things being ‘black or white’ is probably dangerously misleading.

So, what can we take from this article and the related research?

Well, certainly not that it’s always going to be OK to be overweight. But, perhaps that we put too much stock in BMI calculations? Especially when this calculation (weight in kilograms divided by the square of your height in meters) does not take into account the extra weight carried in muscles, an individual’s body shape, fat distribution across the whole body or overall fitness level – all of which are important indicators of whether or not the weight we carry could be harmful. In fact, many of the academics studying this paradox suggest that it may actually be caused by problems related to the BMI measurement rather than any actual protection afforded by excess weight. That means that if you eat well and exercise regularly, even If your BMI is high, you are probably going to be healthier than someone who eats badly, smokes, and rarely gets off the sofa (whatever their BMI). At the end of the day it’s just a number, we all know how healthy our lifestyles are so we shouldn’t believe that such measurements can 100% predict our health outcomes. Hopefully, in the future, researchers can plan studies which allow them to look beyond BMI and work out how different types of fat, where it’s stored on the body and our overall fitness level affect our health – this might give us a better picture of what is really good for us.

Post by: Sarah Fox

References:

Excess deaths associated with underweight, overweight and obesity

The Obesity Paradox: Perception vs Knowledge

Obesity Paradox Does Exist

 

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