A new study associates Perfluoroalkyl substances (PFASs), the chemical that helps create non-stick surfaces, with weight regain. But how great is the risk, really?

By Liz Steelman
February 16, 2018

 

They’re lingering in your food packaging, paper plates, and your favorite non-stick pan: They’re Perfluoroalkyl substances (PFASs), man-made chemicals that help make things stain-resistant, waterproof, and stick-proof. But animal-based studies have shown that they could negatively affect your health, causing increased cholesterol levels, suppressed immune systems, thyroid disruption, and even cancer. And a new study is making us think we should be grabbing our trusty cast iron pan instead (even if it is harder to clean). Harvard scientists found that eating food exposed to PFASs might even have something to do with that pesky weight lingering around your belly.

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For the two-year weight loss study, published on PLOS Medicine, an online peer-reviewed non-profit academic journal, 621 overweight and obese participants were randomly assigned a diet to follow for 24 months. Every six months, researchers checked vitals and signs of body change, as well as took plasma samples. At the end of the study, it was clear that participants lost the most weight in the first six months, and then gradually regained some of the weight back during the remaining 18 months. This isn’t new information, but it’s helpful to know that research is continually showing that there’s a sweet spot for weight loss.

But things got even more interesting when researchers looked at plasma samples taken throughout the study. They found that participants who had higher baseline levels of PFASs at the start of the study were the ones most likely to regain weight after the initial loss period. This correlation was most prominent for women: Those with high baseline levels of PFASs regained 1.7 to 2.2 more kilograms (3.7 to 4.8 pounds) compared to those who had lower levels of PFASs to begin with. Researchers suspect this might have to something to do with how these substances affect resting heart rate: For the first six months of the study, those with high baseline PFASs levels experienced the most dramatic decline in resting metabolic heart rate (RHR) and did not experience a subsequent climb in RHR when they regained weight—something that did happen to those with lower PFASs levels.

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It’s good to point out that though researchers have been studying PFASs for a while, this is the first time they’re seeing a correlation between weight gain and PFASs exposure. In the analysis of the study, researchers said that they couldn’t account for the effects of how socioeconomic status and lifestyle factors might play into findings. Additionally, they admit the study might have been skewed if participant’s weight gain was caused by a relapse into their old diet containing high-calorie foods contaminated by PFASs. So while there might not be a definitive reason to throw away all your beloved non-stick pans, it is something to think about when you’re cooking dinner.