Concerns about the health risks of yo-yo dieting may be overstated, according to a comprehensive review published on June 24. The analysis, conducted by Professor Faidon Magkos from the University of Copenhagen and Professor Norbert Stefan from the German Center for Diabetes Research, examined a wide range of studies on repeated weight loss and regain.
The researchers reviewed observational studies, clinical trials, and animal research to assess the effects of weight fluctuations on body composition and metabolism. They found that many associations between yo-yo dieting and poor health are not supported as causal relationships. The review noted that much of the existing research relies on self-reported weight data, making it difficult to determine cause and effect or whether weight changes result from intentional efforts or underlying illness.
Professor Stefan said, "When you take into account existing disease, ageing, and overall exposure to obesity, the supposed harmful effects of yo‑yo dieting largely disappear." Magkos added that when individuals regain lost weight after dieting, they return to their previous level of risk rather than increasing it: "When the weight returns, you move back towards a level of risk similar to before—not beyond it. There is a crucial difference between losing benefits and causing harm."
The review highlighted that the degree of obesity itself appears to be a more significant factor in metabolic disease risk than fluctuations in body weight. The authors also addressed concerns related to new widespread use of weight-loss medications followed by possible regaining: intermittent periods of lower body weight can still provide meaningful improvements in metabolic health even if not maintained permanently.
According to Magkos and Stefan, most people who achieve long-term weight loss have experienced several unsuccessful attempts beforehand. They emphasized, "People with overweight should not be discouraged from attempting to lose weight, even if they find it difficult to maintain in the long term. Unsuccessful weight‑loss attempts are not harmful, but giving up altogether may be." The researchers challenged prevailing interpretations that label repeated cycles of losing and regaining weight as inherently dangerous.
