Diet and Exercise: A Powerful Duo for Combating Harmful Belly Fat
Table of Contents
A combined approach to improving diet and increasing physical activity is significantly more effective at preventing weight gain – and notably dangerous abdominal fat – than focusing on just one behavior, according to new research published on November 21, 2025, in JAMA Network Open.
The study underscores the importance of holistic lifestyle changes for long-term health and disease prevention. Researchers found that simultaneous improvements in both diet and exercise yielded the greatest reduction in body fat, while focusing on just one aspect had limited impact.
Visceral fat, the type of fat that accumulates around the organs in the abdomen, is strongly linked to an increased risk of serious health conditions, including type 2 diabetes, fatty liver disease, and heart disease.
“When people talk about changes in body weight, they frequently enough refer to a single number on the scale,” one researcher explained.”But not all weight loss or gain is the same. We need to focus on fat mass and where these changes happen.”
Seven-Year Study Reveals key Insights
The research, conducted by the Medical Research Council (MRC) Epidemiology Unit at the University of cambridge, followed 7,256 adults participating in the Fenland Study over a seven-year period. Participants, with an average age of 49 at the study’s outset, had their physical activity levels measured using wearable heart rate and movement sensors for at least 72 hours. Diet quality was assessed through questionnaires evaluating adherence to the Mediterranean diet – a dietary pattern rich in fruits, vegetables, whole grains, legumes, nuts, olive oil, fish, and poultry, with limited red meat and sweets.
Researchers utilized DEXA scans,a low-intensity X-ray technology,to measure body fat distribution and ultrasound to detect fatty liver disease. The analysis revealed that improvements in both diet and physical activity were independently associated with reductions in overall body fat, subcutaneous fat, and visceral fat, and also a lower incidence of fatty liver disease.
Synergistic Benefits of Combined Lifestyle Changes
The most significant benefits were observed when participants improved both their diet and activity levels. Individuals who adopted both healthier habits gained,on average,1.9 kg less total body fat and 150g less visceral fat over the follow-up period compared to those who did not make any changes. This represents approximately 7% of baseline total body fat and 16% of baseline visceral fat.
Notably, the association between changes in diet and physical activity with visceral fat remained significant even after adjusting for body mass index (BMI), suggesting that visceral fat is particularly responsive to lifestyle interventions. .
“We found that combining a better diet with more physical activity is an effective way to improve not just weight, but how much and where fat is stored in the body,” stated Dr. Shayan Aryannezhad, the study’s first author from the MRC epidemiology Unit. “It’s particularly effective at reducing the build-up of harmful fat around organs.”
implications for Public Health
senior author Professor Nita Forouhi emphasized the broader implications of the findings. “Our research shows that improvements in diet with more physical activity in middle-age don’t just result in weight loss, but can potentially help prevent disease and support healthier ageing,” she said.
Professor Forouhi also highlighted the need for systemic changes to promote healthier lifestyles. “Despite the challenges of living in environments that promote unhealthy eating and inactivity, there is benefit from making small, sustained changes that lead to both healthier diets and increased energy expenditure. To address the epidemic of obesity and its huge social, psychological and health service costs, policy makers should seek to alter the food and physical activity environments to make healthier choices more accessible for all.”
The research was funded by the Medical Research Council and the Wellcome Trust, with support from the NIHR Cambridge Biomedical Research Centre.
Source: Aryannezhad, S et al. Concurrent Changes in Diet Quality and Physical Activity and association With Adiposity in Adults. JAMA Network Open; 21 Nov 2025; DOI: 10.1001/jamanetworkopen.2025.45232
