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Staying Slim: What’s More Effective, Exercise or Healthy Eating?
- November 24, 2025
- Ernie Mundell HealthDay Reporter
When it comes to warding off excess fat, boosting exercise levels while improving your diet may be most effective, rather than focusing on either exercise or diet alone.
That’s the finding from a seven-year study of almost 7,300 British adults.
“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,” noted study lead author Dr. Shayan Aryannezhad. He helped conduct the research while at the University at the University of Cambridge’s Medical Research Council (MRC).
There’s an added bonus to the exercise-diet combo, Aryannezhad said, because "it’s particularly effective at reducing the build-up of harmful fat around organs.” He left the MRC’s epidemiology unit earlier this year and is now a clinical research fellow at the University of Oxford.
For the study, Aryannezhad and colleagues wanted to tease out the types of body fat lost under various weight-loss strategies.
“When people talk about changes in body weight, they often refer to a single number on the scale,” he explained in a Cambridge news release.
“But not all weight loss or gain is the same. First of all, we need to focus on fat mass when considering the risk of metabolic diseases like diabetes and heart disease. Second, body fat is stored in different places, and some types are more harmful than others. So, when we gain or lose weight, it matters where these changes happen," Aryannezhad said.
So-called “visceral fat” stored around organs is strongly linked to type 2 diabetes, fatty liver disease and heart disease, the study authors pointed out.
In their study, published Nov. 21 in JAMA Network Open, Aryannezhad’s team tracked the diets, activity levels and fat levels of almost 7,300 Britons averaging 49 years of age when the 7-year study began.
Folks who engaged in either improving their diet only (adhering more closely to the heart-healthy Mediterranean Diet) or boosting their daily physical activity only helped keep weight gain at bay, including fat buildup under the skin and around organs, the researchers reported. The effect tended to be “modest,” however.
Much more significant benefits were seen among people who bettered both their diets and their activity patterns, according to the study.
This dual approach led to weight gain over seven years that averaged about 4 pounds less than people who didn’t alter their behaviors, and they also had 150 grams (about 5 ounces) less dangerous visceral fat by the study’s end.
After even more detailed analysis, the researchers found that the combo of changing diets and exercise was especially beneficial in warding off visceral fat.
"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 aging," study senior author Nita Forouhi, program leader at MRC Epidemiology, said in the news release. “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.”
More information
There's more on the impact of visceral fat on health at Harvard Health.
SOURCE: University of Cambridge, news release, Nov. 21, 2025
