By Grace van Deelen
When Dr. Rob Sargis sees a patient struggling with obesity, his recommendations go beyond diet and exercise. He may advise them to stop heating things in plastics or to avoid congested roads during rush hour.
Sargis, a practicing doctor and professor of medicine at the University of Illinois, is one of a number of doctors incorporating the science of obesogens — endocrine-disrupting chemicals that spur obesity — into their clinical practice.
Obesogens are a subset of endocrine-disrupting chemicals — man-made compounds that alter hormone activity.
They are generally defined as any chemical that can cause the human body to produce more fat than it normally would, and can include substances we usually think of as fattening, like sugars or artificial sweeteners.
However, obesogens are not only found in food, rather entering the body through other consumer products, like makeup, shampoos, soaps, plastics and food packaging.
People are exposed through contact with the chemicals and through ingestion of contaminated foods. The chemicals are also shed from such products and can accumulate in household dust, which people breathe in.
PFAS, or per- and polyfluoroalkyl substances (toxic chemicals used in many consumer and industrial products) are another example of obesogens, as is bisphenol- A (BPA).
By disrupting hormone activity, these chemicals can spur obesity in a number of ways. They can alter metabolism, cause the body to produce new fat cells, alter eating behavior, and even change the way food is digested.
To Sargis, incorporating an understanding of obesogens into clinical practice is part of the goal of medicine as a whole: to build a healthier society.
Obesogenic chemicals have other harmful health impacts too — for example, PFAS and BPA are also linked to certain cancers and reproductive problems. Reducing obesogen exposure is beneficial across the health spectrum.
Sargis told EHN:
“What we’ve seen in medicine over the last few years is this shift from individual factors, like genetics, lifestyle and diet, to an embracing of the social determinants of health, including things like food, environment, exercise and education.”
However, Sargis and other doctors interested in using the obesogen framework face barriers, such as difficulties gathering data on obesogens, a bias toward focusing on diet and exercise, and inadequate medical school training in environmental exposures.
In addition, a lack of regulation of obesogens makes it hard to reduce the exposures — even for patients who are aware of the risks.
“The challenge is that there are systemic forces that you have to fight, and a lot of that’s policy, and a lot of that policy is embedded in politics.”
Lack of data
A major obstacle to incorporating an understanding of obesogens into clinical practice is that doctors are sometimes not convinced by the data available. While plenty of data exists to show a correlation between obesogen exposure and obesity, there is less data that shows that if a person reduces their obesogen exposure, they can lose more weight.
Gathering that data is difficult, but possible, said Sargis. However, the ubiquity of obesogens in everyday products, as well as the lack of transparency from companies about the chemicals in their products, makes designing such a study difficult.
The sheer number of chemicals that would need to be tested — there are more than 9,000 types of PFAS, for example — also adds to the challenge.
Jerry Heindel, a biochemist and founder and director of HEEDS, a coalition of researchers advocating for better regulation of chemicals, told EHN that doctors and patients could benefit from an accessible and cheap way to measure exposure to obesogens.
That way, patients could hypothetically see if their exposure levels drop over time as they worked to eliminate obesogens from their daily life. For now, he said, patients would need to pay for the tests themselves, but he hopes insurance would cover the tests in the future.
Jenna Hua, a doctor-turned-CEO of medical testing company Million Marker, thinks her company’s product could play a role. Million Marker offers at-home test kits that measure the levels of 13 common endocrine disruptors, some of which also act as obesogens, in a person’s urine.
The tests are able to detect BPA, two BPA alternatives, five types of phthalates, four types of parabens, and oxybenzone.
It’s “quite empowering,” Hua told EHN, when someone using the tests can see their exposure levels drop as they swap out products they’re using that include obesogens.
The type of testing that Million Marker offers would be another tool in managing weight loss.
“It would not be possible to tease out what part of weight gain is due to obesogens. The doctor would have to explain to the patient all the possibilities and how to address each of them to reduce their weight.”
As more patients recognize that obesogen exposure is a threat to their health, Hua said, the public may be more inclined to pressure governments to regulate endocrine-disrupting chemicals.
Most obesogens are not currently regulated in the U.S., for example, the U.S. Food and Drug Administration (FDA) does not restrict the use of BPA in food packaging, and there are no federal standards limiting PFAS discharges in drinking water.
Bias toward individual factors
One of the reasons that obesogens have been overlooked, Sargis said, is that treatment of obesity is biased toward individual factors like diet and exercise.
“There’s an inherent bias that this is somehow a personal failing,” said Sargis.
That kind of thinking, he said, might be rooted in conventional beauty standards and the idea that obesity is an aesthetic problem more than a health problem.
Research has shown that in the U.S., obese individuals are often highly stigmatized and labeled as lazy, unmotivated, and lacking in self-discipline.