Chemicals in Everyday Products Are Spurring Obesity, Warns a New Review

Prevalence of self-reported obesity among U.S. adults by state, 2020. (Credit: CDC) In the U.S., obesity has risen steadily over the past decades, from 30% of adults in 2000 to 42% of adults in 2018. Obesity in children has risen as well, from 14% in 2000 to 19% in 2019. People think about obesity mostly in the context of calories—if you eat more calories than you burn, you’ll gain weight. To deal with obesity, many clinicians will advise reducing the number of calories eaten and increasing exercise. Diet and exercise undoubtedly play a major role in obesity levels. However, the persistent rise in obesity in the U.S. indicates to Heindel that something besides diet and exercise is at play. But with the lack of available tests to determine whether a person might be suffering from obesogen exposure or not, scientists are still unsure of the role that obesogens play in proportion to other factors like diet and exercise. “There are so many multiple different factors going on, that we can’t pinpoint which one is doing what,” said Heindel. Doctors and healthcare workers, he added, are “focused on the fact that obesity is due to over-eating. So if you are obese, you can take drugs, you can be on a diet, or you can have surgery. And that’s supposed to take care of the obesity.” Bruce Blumberg, a professor of developmental biology at the University of California, Irvine and an author on the reviews, agrees. “That’s still the view of the medical community, that obesity really has everything to do with calories and activity and not much to do with anything else,” he told EHN. The Centers for Disease Control, for example, does not list obesogens as a driver of obesity; instead, it lists diet, activity, sleep, and genetics. Ryan Baldwin, a spokesperson for the American Chemistry Council, an organization representing more than 190 chemical companies, pushed back against the new reviews. “The prevailing view among the mainstream medical community is that obesity results from an imbalance between energy intake and expenditure caused by poor nutritional choices and insufficient exercise,” he wrote in a statement to EHN. “The evidence to support this view is much larger and of much higher quality compared to the evidence cited by Heindel [and co-authors] to support their obesogen hypothesis.” Who’s Most Vulnerable? While exposure to obesogens as an adult can cause weight gain, there are specific periods in development when people are most susceptible to obesogen exposure. Exposure is a particularly important consideration for pregnant people, the review warns, as the chemicals can pass through the placenta and affect the development of a fetus’s metabolic system in utero. That exposed fetus will have a higher risk of obesity later in life. Young children are also more vulnerable to obesogens. During early childhood, the metabolic system is still under development, and susceptible to chemical influences. The changes that these metabolic systems undergo in early childhood — such as obesogen exposure — are carried through to adulthood, putting the child at a higher risk of obesity. Avoiding Obesogens Individuals can reduce their exposure by avoiding pre-packaged or processed foods, which often come in containers made with obesogens like PFAS or other plastic additives. Avoiding fruits and vegetables treated with pesticides, or washing produce that has been sprayed, is another way to reduce exposure. The authors of the reviews urge that obesogen exposure is such a widespread public health problem that it should be dealt with through regulation. For example, said Lustig, the Environmental Protection Agency should take responsibility for testing for and regulating such chemicals. That’s not happening, said Blumberg, because of a lack of will and funding within the EPA. “The EPA is heavily influenced by the industries that are regulated … that’s not the way they’re supposed to work,” he said. Regardless, said Heindel, “it’s hurting peoples’ health, and hopefully [governments] will pay attention to that and act accordingly.” This story was originally published on the Environmental Health News blog.