The 'Obesogen' Myth: Chemicals Don't Cause Weight Gain

The activists at Environmental Working Group (EWG) consistently butcher the science on a variety of consumer health issues. They're wrong about the dangers of pesticide exposure; they're wrong about the environmental impacts of meat consumption. They're wrong about contaminants in drinking water; they're wrong about cellphone radiation; they're also wrong about antibiotics in the food supply. Search our archives: there are plenty more examples where these came from.

I bring up EWG's underwhelming track record because the organization has again waded into the obesity debate with a terribly misleading blog post titled Are food and consumer product chemicals contributing to our obesity crisis? The answer is “no.” There has never been sound evidence behind this hypothesis. It persists because many epidemiologists, activists, politicians, and reporters make a living by calling attention to and solving non-existent problems. If you think that's too harsh, read on as we examine EWG's specific claims in quotes, followed by my commentary.

The food industry insists America’s obesity crisis can be chalked up to simple math – people eat too much and exercise too little.

Obesity is more complicated than simple addition and subtraction. As this 2017 paper explained, we know “that energy intake and expenditure are interdependent variables that are dynamically influenced by each other and body weight.” There is also a lot of individual variability regarding long-term weight loss. Everything from insulin sensitivity to adequate support from health care providers plays a role.

Nonetheless, research has shown time and again that reducing caloric intake leads to weight loss. People achieve that result on many different diets, but the common denominator they share is an energy deficit. EWG wants to dismiss calorie restriction as a food-industry talking point so they can blame obesity, at least partially, on chemical exposure. They don't want to account for all the complexities of human metabolism; they want to substitute one bromide—BPA makes you fat—for the well-worn bromide that overweight people should just eat less and move more.

Can chemicals found in everything from food and cosmetics to drugs and carpets make it easier for our bodies to build fat? … Many of these chemicals – called 'obesogens' by scientists – alter hormones and metabolism in subtle ways that ultimately make us gain more weight.

EWG linked to a very extensive literature review in support of this assertion. Interestingly, the authors of that analysis had the integrity to highlight significant limitations that restrict the conclusions we can draw about the impact of “obesogens.” These include statistical and methodological issues such as:

Misclassification of exposures with high within-person variability (e.g., for the short half-life chemicals such as BPA), reverse causality due to pharmacokinetic factors (e.g., different routes of exposure affecting the rate of excretion), or inability of the biomarker to represent exposure during the relevant period.

It gets worse. Researchers also have trouble separating the possible effects “of one obesogen exposure from another when exposures are correlated due to common sources,” the reviewers wrote. Is one, some, or all of these chemicals increasing the risk of obesity? Do some substances exert greater obesogenic influence than others?

The problem is amplified by “missing data and exposure below the detection level.” Until these and other limitations are addressed, the case for obesogenic chemicals consists of little more than statistical correlations. Our resident toxicologist Susan Goldhaber summed up the issue recently. Using BPA as an example, she explained that

BPA demonstrates toxicology's fundamental principle: 'The dose makes the poison.' The levels of BPA that people are exposed to are so low that no health effects have been noted; animal studies have only reported adverse health effects at very high levels.

Back to EWG:

The number of people who have overweight and obesity in the U.S. and globally continues to climb, despite our cultural obsession with diet and exercise and myriad efforts to promote healthier diets. Since the 1970s, the number of Americans with obesity has tripled, to 42 percent.

True enough, but it doesn't follow from this observation that chemical exposure is the missing link in the causal chain leading to obesity. Every diet guru with a book to sell has committed this logical fallacy. The fact that a problem persists doesn't mean EWG's idiosyncratic solution is the answer to our expanding waistlines. To draw that conclusion we need solid evidence, and the chemicals-make-you-fat advocates haven't provided it.

Congress should provide more funding to agencies like the EPA and the Food and Drug Administration to review obesogens’ health impacts and close the loopholes that allow chemical companies, not the FDA, to decide which chemicals in food and cosmetics are safe.

Compare the preceding paragraph to what the FDA actually says about the safety of cosmetics. “FDA may take regulatory action if we have reliable information indicating that a cosmetic is adulterated or misbranded,” the agency's website notes. Regulatory action includes seizing products violating federal law and suing the offending manufacturers or distributors. The FDA can also “conduct inspections of cosmetic firms ... without prior notice in order to assure compliance with the applicable laws ... [my emphasis]”

The story is similar for food chemicals. In the case of per- and polyfluoroalkyl substances (PFAS), one of EWG's perennial boogeymen, the FDA states in no uncertain terms that it

… conducts a rigorous review of scientific data prior to their authorization for market entry. The FDA’s authorization of a food contact substance requires that available data and information demonstrate that there is a reasonable certainty of no harm under the intended conditions of use.

Does this sound like a powerless bureaucracy restrained by the heavy hand of America's corporate overlords? Hardly. From the kinds of foods and tobacco products Americans can buy to the breeds of animals farmers can raise for commercial production, the FDA's regulatory authority is stunningly broad. EWG is trying to bamboozle unsuspecting consumers who don't have time to study the finer points of federal chemical regulation.

Ironically enough, an argument could be made that the FDA lacks appropriate regulatory authority, or perhaps the will to exercise it, over some products—those marketed with the Non-GMO Project label. Foods and consumer goods affixed with that stupid butterfly logo include salt, which contains no DNA, as well as a wide variety of products for which there are no GMO alternatives, such as green beans. There are also verified brands of non-GMO cat litter on the market. You'll never guess what EWG thinks of the Non-GMO Project:

Buy food certified as 'Non-GMO Project Verified.' The non-profit organization Non-GMO Project operates a detailed, voluntary certification process so that food producers can test and verify that, to the best of their knowledge, they have avoided using genetically modified ingredients in their products.

We'll end where we began. EWG has again butchered the relevant science and told another highly misleading story about consumer safety. If there really are “obesogenic” chemicals lurking in our grocery stores, the activist group has failed to demonstrate their existence.