A new analysis in The Lancet Diabetes & Endocrinology concludes that repeated weight loss and regain—often called weight cycling—does not appear to cause lasting metabolic damage on its own, after researchers reviewed decades of evidence from human studies and animal models.
A review published online in The Lancet Diabetes & Endocrinology assessed evidence on weight cycling—repeated weight loss followed by weight regain, sometimes referred to as “yo-yo dieting.” The authors, Faidon Magkos of the University of Copenhagen and Norbert Stefan of the German Center for Diabetes Research (DZD) and collaborators in Germany, examined research spanning observational studies, randomized clinical trials and animal experiments.
The analysis found no strong causal evidence that weight cycling itself produces long-term harm in people with obesity, including no consistent evidence of disproportionate loss of lean (muscle) mass or persistent suppression of resting metabolic rate.
The authors also argued that some reported links between weight cycling and negative outcomes weaken once studies account for factors such as pre-existing health conditions, aging and a person’s overall exposure to obesity over time.
At the same time, the review noted that weight regain can reverse many of the short-term improvements seen with weight loss—such as better blood sugar, blood pressure and cholesterol—without necessarily pushing health risk beyond an individual’s pre-weight-loss baseline.
In the article, Magkos said fears that “yo-yo dieting” inevitably damages metabolism and causes muscle loss are “largely unsupported,” and that, in most cases, the potential benefits of attempting weight loss outweigh the theoretical risks tied to weight cycling.
