Mediterranean diet, when coupled with physical activity, can help reduce body fat and prevent muscle loss in older adults, a new study has found.

The study, published in the journal JAMA Network Open, was designed to test the effect of the intervention on cardiovascular disease prevention but in the meantime, a subgroup was assessed to measure the impact on body composition after a three-year period.

The findings revealed that a lower-calorie (energy-reduced) Mediterranean diet and increased physical exercise appeared to decrease ageing-related weight gain and muscle loss.

"A 3-year weight-loss intervention based on an energy-reduced Mediterranean diet and physical activity, compared with advice to follow the Mediterranean diet without weight-loss goals, resulted in significant improvements in body composition in middle-aged and older adults with chronic health conditions," wrote the study authors.

"In particular, we found that this multifactorial lifestyle intervention was effective in reducing total body fat and visceral fat. In addition, the lifestyle intervention led to an attenuation of age-related decreases in lean mass," they added.

A total of 1,521 middle-aged and older volunteers who were either overweight or had obesity and metabolic syndrome were divided into two groups.

The first group followed a Mediterranean diet while reducing their calorie intake by 30 per cent and increasing their physical activity, eventually reaching a 45-minute walk or equivalent six times a week, and the other followed the same diet without calorie restrictions or changes in physical activity.

According to the researchers, the first group experienced "clinically meaningful" changes in body composition throughout the three-year experiment, including a 5 per cent or greater improvement in fat mass, visceral (belly) fat mass and loss of lean muscle mass after only one year of following the diet. However, the other group had negligible changes, the study said.

“These changes are likely of public health and clinical relevance. Given the metabolic relevance of specific body components, especially visceral fat and lean mass, the benefits of this lifestyle intervention could be very promising. However, continued follow-up is warranted to confirm the long-term consequences of these changes on health,” the researchers stated