It’s not just about the number on the scale: The hidden value of so-called ‘yo-yo dieting

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So-called “yo-yo dieting” confers long-term health benefits, according to a new study by Ben-Gurion University of the Negev researchers. “Yo-yo dieting” is a pattern in which individuals lose weight through lifestyle interventions but gradually regain it over time, leading to repeated attempts at weight loss. These cycles may affect not only body weight, but also body composition, particularly visceral (intra-abdominal) fat, a metabolically active tissue linked to cardiometabolic disease. Thus, for many individuals, the key question is not whether to lose weight once, but whether repeated attempts confer long-term health benefits or risks.

According to Prof. Iris Shai, the study’s principal investigator from Ben-Gurion University of the Negev, dean of the School of Sustainability at Reichman University, an adjunct professor at Harvard T.H. Chan School of Public Health, and an honorary professor at Leipzig University, Germany, these findings challenge the traditional focus on weight loss as a simple numbers game. “Persistent commitment to a healthy dietary change creates cardiometabolic memory in the body. Repeated participation in a lifestyle program aimed at weight loss, even after an apparent ‘failure,’ in which an individual regains all the weight lost in a previous diet—may lead to significant and sustainable health benefits over the years, particularly through the reduction of harmful visceral (abdominal) fat.”

Health gains beyond the bathroom scale

Hadar Klein, RD MSc, a doctoral student and lead author, says, “Body weight alone does not capture changes in visceral fat or metabolic biomarkers. Even when weight is regained, cardiometabolic health may remain improved, and success should not be defined solely by the number on the scale. Importantly, even when weight loss is attenuated during a second attempt, the cumulative benefits for abdominal fat and metabolic health are substantial.”

In the new study, published in BMC Medicine, researchers conducted a unique 5- and 10-year follow-up of participants from two consecutive randomized controlled dietary trials (DIRECT-PLUS and CENTRAL), which together enrolled approximately 500 participants. Each trial lasted 18 months and included approximately 300 participants. One-third of the participants in the first trial also took part in the second trial. The trials examined Mediterranean diet–based interventions and physical activity compared with control diets, with detailed MRI scans performed before and after each intervention.

Evidence of lasting cardiometabolic memory

The study found that, surprisingly, although participants entered the second intervention at a body weight similar to that at the start of the first intervention, indicating full weight regain, their abdominal fat profile and metabolic markers were more favorable, with improvements of approximately 15–25% compared with their initial baseline, including enhanced insulin sensitivity and a more favorable lipid profile. This finding points to the existence of a positive “cardiometabolic memory” from prior intervention that persists even after weight regain.

Moreover, although participants who rejoined the weight-loss program lost less weight during the second intervention, they maintained better long-term health outcomes. Five years after completing the second intervention, these participants showed less weight regain and less accumulation of abdominal fat compared with participants who had engaged in a weight-loss program only once.

The trials were conducted at Ben-Gurion University of the Negev, Israel, together with researchers from Harvard, Leipzig, and Tulane and in collaboration with the Dimona Nuclear Research Center, Briuta Medical Center, and Soroka University Medical Center.

Adopting a healthy diet may have cardiometabolic benefits regardless of weight loss