When lost weight returns, it’s easy to assume that all the health benefits disappeared along with it. A new study suggests the reality may be more complicated.
Researchers found that participants who reduced visceral fat during a lifestyle intervention experienced lasting metabolic benefits years later, even though average body weight eventually returned to where it started. Each 10% reduction in visceral fat achieved during the original intervention was associated with a 28% lower risk of developing type 2 diabetes during long-term follow-up. The study does not prove that visceral fat loss directly caused the lower risk or guarantee that an individual person will experience the same result.
Visceral fat is stored deep in the abdomen around internal organs. It’s different from subcutaneous fat, which sits beneath the skin. Although body weight can offer useful information, it does not show where fat is stored or how changes in different fat depots may affect metabolic health.
Published in Circulation, the study followed participants from two 18-month lifestyle trials conducted in Israel. The original trials examined dietary approaches including healthy eating guidelines and Mediterranean diet variations, with structured physical activity included in some study groups. Researchers later invited participants to return for follow-up assessments five and 10 years after the trials ended.
The researchers reached 366 of 381 eligible participants, an unusually high 96% retention rate for a long-term follow-up study. Participants underwent MRI scans that allowed the researchers to examine visceral fat, two types of abdominal subcutaneous fat, liver fat and pancreatic fat. They also completed clinical assessments related to metabolic health.
By the long-term follow-up, average body weight had returned to baseline. But several abdominal fat depots, including visceral fat, remained lower than they had been before the interventions. Waist circumference also remained lower. Liver fat returned to baseline, while pancreatic fat rose above baseline.
The researchers found that reductions in visceral fat during the original interventions were associated with lasting improvements in insulin resistance and other measures of cardiometabolic health. Visceral fat was also the only fat depot whose reduction was independently associated with a lower future risk of type 2 diabetes.
“Our findings suggest that not all weight loss is equal,” said lead author Hadar Klein. “Reducing visceral fat may have a more lasting impact on metabolic health than changes in body weight alone and may help support healthier aging over time.”
The findings may offer a more encouraging way to think about weight regain. Maintaining weight loss over the long term can be difficult. The study suggests that periods of healthier eating and increased physical activity may still matter, even when the number on the scale eventually rises again.
But the results do not mean that body weight is irrelevant. Weight, waist circumference, diet quality, physical activity and fat distribution are interconnected. The study also does not show that losing exactly 10% of visceral fat will reduce every person’s diabetes risk by 28%.
The original studies were randomized clinical trials, meaning participants were assigned to different lifestyle interventions. However, participants were not randomly assigned to lose a specific amount of visceral fat. The long-term analysis examined whether changes in fat distribution were associated with later outcomes. That makes the diabetes-risk finding an important association, not proof of cause and effect.
The study also does not establish that one particular diet is the best way to reduce visceral fat. The participants followed several lifestyle approaches, and the new analysis focused on changes in fat depots rather than declaring a single eating pattern the winner.
For most people, precisely measuring visceral fat is not realistic. MRI scans are useful in research, but they are not typically used as a routine tool for tracking progress. Waist circumference can provide some information about abdominal fat, but it is not a perfect substitute for an MRI scan and should not become another source of anxiety or body scrutiny.
The findings may not apply equally to everyone. The original trials were conducted in a workplace setting and included mostly men. More research involving women and a broader range of populations would help clarify how widely the results apply.
The study received support from the Deutsche Forschungsgemeinschaft, also known as the German Research Foundation, through Germany’s Excellence Strategy and additional project funding. One researcher disclosed receiving honoraria as a consultant and speaker from Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi-Sankyo, Lilly, Novo Nordisk, Novartis and Sanofi.