- As we age, we tend to gain belly fat and lose muscle mass.
- A lower calorie Mediterranean diet combined with light exercise could prevent this, a study found.
- Participants who made these lifestyle changes also lost harmful visceral fat.
As we age our bodies go through changes. We tend to lose muscle mass and gain belly fat, which can be a precursor to health problems such as diabetes and cardiovascular disease.
However, following a lower calorie Mediterranean diet and doing light exercise could prevent or delay these age-related changes, according to a study published on Wednesday in JAMA Network Open.
The study found that the participants, who were aged between 55 and 75 and were either overweight or obese, lost more body fat and less muscle over a three-year period if they ate a lower calorie Mediterranean diet and lightly exercised up to six days a week than those who didn't. Their body composition changed the most in the first year, but they had maintained most of the changes by the three-year mark, the study said.
As well as gaining a better fat-to-muscle ratio, they also lost visceral fat, which sits underneath the stomach muscles and wraps around the abdominal organs, and can lead to heart disease, stroke, and diabetes. Participants lost a moderate amount of fat, but the authors called it "clinically meaningful."
Participants who were given regular guidance by dietitians lost more fat
The study drew on data from an ongoing eight-year Spanish study involving 6,874 overweight or obese participants with metabolic syndrome, an umbrella term for patients with high blood pressure, high blood sugar, low DHL or "good" cholesterol, and excess fat around the waist. Its aim is to test whether eating a Mediterranean diet can prevent cardiovascular disease.
The researchers measured the body composition of 1,521 people from the study at three different stages. The participants were randomly put into either an intervention or control group.
The intervention group ate a 30% reduced calorie Mediterranean diet, received guidance and support from dietitians three times a month, and were encouraged to limit their consumption of processed meats, butter, margarine, cream, sweetened beverages, added sugar, biscuits, and bread. They were also told to walk for 45 minutes a day and exercise to improve their strength, flexibility, and balance.
The control group followed a Mediterranean diet too, but were not told to reduce their calories or exercise more. They were given general advice on the diet twice a year.
Both groups lost some fat but only those in the intervention group lost visceral fat, the study said. They also lost more weight while retaining or gaining more muscle compared with the control group, the study said.
"This study demonstrates that a calorie-controlled Mediterranean diet plus exercise does not simply produce weight loss; it results in a redistribution of body composition from fat to muscle," Dr. David Katz, a specialist in preventive and lifestyle medicine, who was not involved in the study told CNN.
More research is needed before we can know if these changes would hold up long-term
The authors said that more research would be needed to understand if the changes they observed would have long-term effects on the participants' health, and if they would apply to a younger or healthier demographic.
Dr. Christopher Gardner, a research professor of medicine at the Stanford Prevention Research Center in California who directs its Nutrition Studies Research Group and was not involved in the study, told CNN that the three-year follow-up was "most profound" to him.
"The magnitude of the three-year differences are modest, and the trend from one-year to three-year suggests that at six-years the effects may be diminished to insignificance," However, he said that "three-year statistically significant differences are impressive!"
Gunter Kuhnle, a professor of food and nutritional science at the University of Reading, UK, who was not involved with the study, told the outlet: "It would have been much more informative had the control group received a similar high-intention support (even if it only contained generic advice)."
"Motivation and compliance is very important in studies that investigate behavior change, and the study design clearly favored the intervention," Kuhnle said.