Fears of negative health consequences from weight cycling - better known as yo-yo dieting - may be overemphasized, suggests a new study presented at The Endocrine Society's 93rd Annual Meeting in Boston.
"Remaining on a stable, healthy diet provides the best outcome for health and longevity," said study author Edward List, a scientist at Ohio University. "However, obese individuals commonly weight cycle - they have repeated intentional weight loss followed by weight regain, often called yo-yo dieting. While yo-yo dieting is thought to be harmful, there is little hard scientific evidence to support that."
List performed what he says is "the first controlled study of a yo-yo diet regimen used for an entire life span." Because of the challenges of performing a long-term controlled feeding study in humans, they used mice to test whether weight fluctuation due to yo-yo dieting is as unhealthy as lifelong obesity.
The mice received one of three diets: high fat, low fat or a yo-yo diet, consisting of four weeks of the high-fat diet followed by four weeks of the low-fat diet. The mice stayed on their respective diets throughout their life span.
List said the yo-yo diet resulted in large fluctuations in health measures, but when the high-fat and low-fat diet regimens of the yo-yo diet group were averaged, "average health" was improved compared with obese mice that stayed on the high-fat diet. Compared with the mice fed the high-fat diet, mice on the yo-yo diet lived nearly 35 percent longer. "Surprisingly, the mice on the yo-yo diet had a similar life span to that of the low-fat-fed group," List said.
"The fear of negative health consequences due to weight cycling may be overemphasized," List concluded. "It appears that it is better to continue to encourage weight loss regardless of the number of attempts and failures."
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Source: The Endocrine Society