Even if the weight came back on, the diet may have been beneficial - study shows
A decade of observation has shown: repeated participation in a weight loss programme can permanently improve metabolism and reduce visceral fat - even if the person then gains the weight back.
Scientists from Ben-Gurion University (Israel) have concluded that the so-called "yo-yo diet " - when a person loses weight, then gradually gains weight and tries again - is not necessarily harmful. What's more, repeated attempts can provide long-lasting health benefits, even if the weight eventually comes back off.
The researchers followed participants in two large diet clinical trials: first CENTRAL (2012-2014), then DIRECT-PLUS (2017-2018). Both programmes lasted 18 months each and included Mediterranean-style diets and lifestyle changes. A proportion of people participated in both programmes and then all were invited for follow-up surveys in 2022-2024.
The main feature of the work was MRI measurements: the scientists looked not only at total weight, but also at visceral fat (fat inside the abdomen around organs), which is more strongly linked to risk of diabetes and heart disease.
What came up:
many participants who came into the second programme started at roughly the same weight as they were at the start of the first - meaning the weight may have come back off completely;
but their 'belly picture' and metabolic performance was better than at the very first start: the authors describe improvements in the order of 15-25% in a number of parameters (including insulin sensitivity and blood lipids). This they call "cardiometabolic memory " - the effect of past healthy changes that persists even after weight gain.
Another finding: people often lost less weight in their second attempt than they did in their first. But several years after the second programme, they had, on average, less re-gain and less belly fat accumulation than those who underwent a weight loss programme only once.
The authors emphasise: this is not a call to "swing the weight" on purpose. The point is different - efforts to improve diet and habits can be beneficial, even if the weight comes back, and success should not be measured by the number on the scale alone.