Is being fat a health risk in and of itself? The prevailing currents in obesity research as well as federal government policies that allow diet-related costs to count as tax-deductible expenses certainly support this notion. But University of Colorado-Boulder law professor Paul Campos says, hold the horses! In a hotly controversial 2003 cover story published in The New Republic, a liberal politics and culture magazine, Campos argued that an objective analysis of the existing research shows that fat is not actually an independent health risk – but rather, that our obsession with fat and our societal craze for dieting is. We think his article, which has recently been posted to The New Republic's website, bear some re-examination as we move forward into another new year filled with weight-loss resolutions.
"The war on fat is based on many things," Campos writes. These include the neurotic relationships Americans have with food and their own self-images, as well as the financial interests of the diet industry. But, he argues, the 'war on fat' is not based on the most crucial factor of all: the projected health risks of being overweight. In a review of the literature, he concludes that the majority of research actually shows that being fat, per se, does not translate to premature mortality. What does is a sedentary lifestyle that includes little or no physical activity. Another factor associated with lower life expectancy is, ironically, high rates of dieting and diet-drug use. Remarkably, he reports, longitudinal studies performed by the Cooper Institute and Harvard and Yale Universities have shown that neither body mass nor body fat percentage is linked to health. These studies instead found that overweight people who engage in moderate levels of physical activity enjoy lower rates of premature death than thin people who lead a sedentary life or who frequently use diet-drugs.
These are interesting data, to be sure, but we note that Campos' cautions about the difficulty of separating confounding variables cut both ways. He points out that the observational studies that have linked BMI to mortality do not actually prove that fat is the cause of higher mortality, rather than confounding variables such as junk food and dieting. We would argue that the converse is also true – the Cooper Institute and Harvard/Yale studies do not prove that fat isn't a risk factor because it could have been masked by confounding variables. After all, from a physiological standpoint, we do know that high adiposity is associated with metabolic syndrome, inflammation, and dyslipidemia – all of which are strong risk factors for cardiovascular mortality. It's difficult to perform studies that parse out how much of this is caused by being sedentary and how much is caused by the fat itself, but the prevailing evidence strongly suggests that BMI and exercise levels are both independent predictors of overall mortality. For overweight and obese individuals with metabolic syndrome, small decreases in body weight (~5%) produce big metabolic benefits regardless of how the weight loss is achieved – through exercise or dieting. Conversely, even people who exercise without losing weight tend to lose some visceral fat – the "bad" fat associated with metabolic conditions – in favor of subcutaneous "good" fat.
We like Campos' thought-provoking discussion of flaws in obesity research, but we don't think these flaws justify throwing the baby out with the bath water. While he is right to raise doubts about the motives and impartiality of obesity studies done on the diet industry's dime, just because a study is industry-funded does not make it scientifically invalid. What we enjoy most is the way he challenges readers to think about what matters more: losing weight or becoming more active. Although his views fall on the extreme side for completely dismissing the role of fat, he is right that Americans has been obsessing over their waistlines for [mostly] the wrong reasons. Many of the misgivings we have about being fat are psychological in nature and may not have the iron-clad medical backing we think they do. This doesn't mean that being overweight is a good thing, but we think Campos is right in saying that we would benefit from a shift in focus away from body mass and toward physical activity – which helps with weight loss, in any case.
Campos ultimately leaves his readers with the message that the most potent treatment for staying healthy is a lifestyle change, not a diet pill. Make sure, he suggests, that you incorporate at least a brisk half-hour walk or some equivalent into your daily routine and you will do a great deal for your health in the long run. Considering the dangers and low efficacy associated with currently available weight-loss drugs, and the biological mechanisms that make us see-saw to ever higher weights when we diet too often (yo-yo dieting, anyone?), we would agree with him. All in all, physical activity does seem a lot safer, but it would take a bit more optimism than we have to think that an article in The New Republic is going to change decades of increased laziness.