I recently wrote about current trends world wide in obesity. The quick summary – it is not only increasing, it’s accelerating, and it’s world-wide, not limited to industrialized nations. Obesity is an independent risk factor for various disease, such as type II diabetes, which itself is a risk factor for complications like heart disease and stroke. Obesity is now the number one preventable cause of life-years lost (recently overtaking tobacco use). So it is reasonable to consider overweight and obesity a serious health problem.

Understanding the causes of obesity is therefore critical. It’s difficult to fix a problem when you don’t know the cause. A recent psychological review outlines what prior research has shown. First, there is no evidence that obesity correlates with independent measures of will power. Rather, obesity correlates with certain biological, lifestyle, and environmental factors.

The biological factors include genetics, brain chemistry, and even our gut microbiome. Genetics alone, however, is clearly not the full answer, because it would be unable to explain the clear rise in obesity rates in the last half century.

Lifestyle factor involve things like one’s job. If your job is sedentary and does not afford much opportunity for physical activity, that is a major risk factor for obesity. Environment plays into this as well. Living location, which also may not afford much opportunity for exercise, is a factor. Access to healthful food is also important.

Psychologically, the main factors that seems to correlate with obesity is life stress. The review notes:

Psychological experiences also play a big role, the report says, with up to half of adults attending specialist obesity services having experienced difficulties in childhood.

Perhaps one of the most significant conclusions of the review is that fat shaming is counterproductive. It does not motivate people to lose weight, and lack of motivation is likely not a contributing factor to obesity in the first place. Rather, fat shaming simply adds to their psychological stress and low self-esteem, which exacerbates obesity.

For example, a 2013 longitudinal study found:

Participants who experienced weight discrimination were approximately 2.5 times more likely to become obese by follow-up (OR = 2.54, 95% CI = 1.58–4.08) and participants who were obese at baseline were three times more likely to remain obese at follow up (OR = 3.20, 95% CI = 2.06–4.97) than those who had not experienced such discrimination.

What this means is that we need to remove the stigma of obesity from our public health messaging. This can be tricky, because we want to communicate that obesity is a health problem that needs to be addressed. But we don’t want to add to the stigma attached to obesity, or imply blame or shaming. To show how tricky this can be, a recent public information campaign by Cancer UK tried to inform the public about the increased risk of cancer from obesity. In order to make this point more impactful, they showed a pack of cigarettes with the brand name replaced by “obesity”, to bring home the fact that obesity can be just as much a risk factor for some cancers as smoking.

In response the ad campaign was accused of fat shaming. There has been pushback against the pushback, however, with some commentators claiming we are abandoning personal responsibility.

This is one of those situations where both sides have a point, and there is a nuanced position in the middle. We do need to communicate basic scientific facts to the public. Obesity is a health risk factor, including for certain cancers. But – the ultimate goal of public service announcements is to have a positive impact on behavior. What matters most in the ends it – does the messaging work?

This is a case where, to some extent, perception is reality. When people perceive they are being fat shamed or discriminated against because of weight, that adds stress which leads to more overeating, exacerbating obesity. There is also the fact that simply knowing about a health risk does not alter behavior.

So in this case I do think the critics of the Cancer UK ad campaign are mostly right. Giving the public information about the risks of obesity is not effective, and to whatever extent there was a perception of fat shaming the campaign was counterproductive. But we don’t want to go too far and make it impossible to discuss scientific facts in public. We just need to be careful about our messaging.

So what, then, would work to turn this obesity ship around? I think the short answer is, we don’t really know (because we haven’t been able to do it yet). But our best guess is that we need to make systemic changes to the environmental contributors to obesity. This means organizing the institutions of life, such as work, so that people have the opportunity to get physical activity and that it is built into the day more routinely. Further, we need to address food insecurity and access to healthful food. We also need to address the “supersized” culture. It is extremely difficult, for example, to eat out without consuming far more calories that you intend or should. We are simply living in a culture with access to massive amounts of stealth calories.

Calorie labeling at the point of purchase has had mixed results when studied scientifically, but reviews conclude that overall, at the population level, there is no apparent benefit. It may still be useful for many individuals, however, if they incorporate that into their weight management strategy. But as a public health measure, it is not enough.

A tax on sugary drinks may be effective. One study found a 52% drop in consumption over three years following the start of the tax. This approach needs further experience and study, however.

I also think we need to directly confront pseudoscience in the wellness/weight loss industry. This industry is mostly peddling misinformation about weight loss, fad diets, and demonizing foods that are not the problem.

Overall it seems that we need a culture change to significantly tackle the obesity problem. It is likely a culture change that is causing the epidemic in the first place, and we need a further change to permanently change people’s habits. Going on a diet does not seem to work. The vast majority fail long term. Permanent lifestyle changes are necessary, and these require institutional and society change. And one thing is for certain at this point – fat shaming not only doesn’t work, it is counterproductive.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.