Can yo-yo dieting actually be good for you?

By Stephen Beech

Yo-yo dieting can actually be good for you, suggests a new study,

Also known as weight cycling, it involves repeatedly losing weight through strict dieting, only to regain it - and often more - over time, leading to repeated attempts to shed the pounds.

Yo-yo dieting has been criticised as previous research has shown it can increase the risk risk of a heart attack, stroke, diabetes, and higher blood pressure.

But a major new study, published in the journal BMC Medicine, shows yo-yo dieting confers long-term health benefits by reducing levels of harmful abdominal fat, also known as visceral fat.

The findings of the largest long-term MRI-based repeated weight-loss trials demonstrate that every weight loss attempt has the potential to improve overall well-being.

Study principal investigator Professor Iris Shai says the research challenges the traditional focus on weight loss as a simple "numbers game".

Shai said: “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 fat.”

Lead author Hadar Klein, a doctoral student at Ben-Gurion University of the Negev in Beer-Sheva, Israel, said: “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."

For the study, researchers conducted a unique five- and 10-year follow-up of participants from two consecutive randomized controlled dietary trials.

Each trial lasted 18 months and included around 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.

The study found that, surprisingly, although participants entered the second intervention at a body weight similar to that at the start of the first one, indicating full weight regain, their abdominal fat profile and metabolic markers were more favorable.

They showed improvements of around 15% to 25% compared with their initial levels, including enhanced insulin sensitivity and a more favorable lipid profile.

The researchers say their findings point to the existence of a positive “cardiometabolic memory” from prior intervention that persists even after weight regain.

The study also showed that, although participants who rejoined the weight-loss program lost less weight during the second intervention, they maintained better long-term health outcomes.

Shai added: "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."