“Chemicals known as perfluoroalkyl substances (PFAS)—used frequently in fast-food wrappers and other products for their oil- and water-repellant properties—have been linked to hormone disruption, immune dysfunction, high cholesterol and even cancer. Now, a new study suggests that exposure to the chemicals could make it harder to keep weight off after dieting.

The study, published in PLOS Medicine, found that levels of PFAS in the blood were linked to greater weight gain in a group of people who had recently shed pounds, especially among the women. Another finding may hint at why: People with higher blood levels of PFAS also had lower resting metabolic rate, meaning they burned fewer calories during normal daily activities…

In the new study, people were placed on heart-healthy diets, and they lost an average of 14 pounds in the first six months. They also gained back an average of 6 pounds over the next year and a half. Researchers found that the amount of PFAS in people’s bloodstreams didn’t affect how much weight they lost during the study. But it did seem to affect what happened next.

Those who gained the most weight back had the highest blood concentrations of PFAS. The link was seen almost exclusively in women: those in the top third for PFAS blood levels regained 2.7 to 4.9 pounds more than women in the lowest third…

It’s possible that people with higher PFAS concentrations in their blood at the start of the study ate more packaged and fast foods—a common source of these chemicals—and were more likely to relapse later and revert back to high-fat, high-sugar food options, researchers say. But they did control for socioeconomic and lifestyle factors in the new analysis (including cravings for hamburgers, French fries and donuts), and they say the findings remained unchanged.”

Read the full article by Amanda MacMillan