Yo-yo dieting is a global phenomenon . About half of adults  are trying to lose weight, but many regain substantial weight once they stop dieting, leading to repeated cycles of loss and gain. A comprehensive review published this May in The Lancet Diabetes & Endocrinology  analyzed decades of observational data, clinical trials and animal models. The findings showed no evidence that weight cycling permanently slows metabolism, causes disproportionate muscle loss or results in long-term harm to obese patients.

The researchers noted that regaining weight typically returns health and metabolic markers to pre-dieting levels, causing dieters to lose the temporary health improvements they experienced when they were lighter. Professor Faidon Magkos, of the University of Copenhagen, a co-author of the study, stated that the benefits of attempting weight loss outweigh the theoretical risks of weight cycling.