PFAS exposure associated with weight loss relapse in a European dietary study

Research findings of Philippe Grandjean, PhD, and Pál Weihe, PhD, leads on STEEP Project Two: Critical Effects, were featured prominently in a recent New York Times article, ‘Forever Chemicals’ Are Everywhere. What Are They Doing to Us?

Obesogens is a new term for industrial chemicals that have been recently linked to increased weight gain and difficulties maintaining weight loss. Obesity and weight loss are complicated issues with multiple contributing factors, making long-lasting weight loss treatments desirable, yet difficult to attain. Weight loss studies have shown mixed results on the benefits of diets and weight loss programs, which suggest that there may be other factors that prevent patients from achieving desired results. There is increasing evidence that exposure to environmental contaminants including PFAS may have an effect on the ability of a person to lose weight and maintain long-term weight loss. STEEP researchers at Harvard University and University of Rhode Island recently collaborated with public health researchers in Denmark to examine the effect of PFAS exposure on weight loss.

Researchers used available data from a European weight loss study called DioGenes, which was conducted between 2006 and 2008, across eight European countries. The original study found that high protein and low glycemic index was successful in helping maintain weight loss in adults, though individual responses varied widely, and some participants experienced a relapse of weight gain after the study. The recent study tested samples of plasma for PFAS from each of the study participants who had achieved the target 8% weight loss during the original study to test whether some of this variability was correlated with PFAS levels in their plasma. They found that certain types of PFAS, specifically PFOA and PFOS, were significantly associated with increased weight gain after initial weight loss. This suggests that exposure to PFAS and other industrial chemicals may be disrupting metabolic processes in people.

PFAS are widespread in the environment due to their frequent use in industrial substances like Aqueous Film-Forming Foams (AFFFs) and everyday materials, like food packaging, nonstick cookware, and textiles, and are consistently found in human blood. These concerning results raise the importance of preventing, or reducing, PFAS exposure wherever possible.

Grandjean, P., Meddis, A., Nielsen, F., Sjödin, A., Hjorth, M.F., Astrup, A., Budtz-Jørgensen, E. 2022 Weight loss relapse associated with exposure to perfluorinated alkylate substances. Obesity. 31:1686–1696. DOI: