Cutting 250 calories a day may boost heart health

Reducing calories from the diets of aging, obese adults had greater health benefits when combined with regular exercise.

Dave Yasvinski 4 minute read August 2, 2021
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Eating better, plus daily exercise was shown to improve the cardiovascular health in people with obesity. GETTY

Pairing aerobic exercise with a reasonable reduction in caloric intake leads to healthier hearts in older, obese adults, according to a new study that proves moderation is a major ingredient of cardiovascular health.

The study, published in the journal Circulation, found that cutting 250 calories from the daily diets of aging, obese adults generated greater health benefits than more restrictive diets, or no diets at all, when combined with regular exercise. While previous studies have shown that aerobic exercise alone has positive effects on the structure and function of the human heart, it may not be enough to offset the stiffening of the aorta in obese people as they age. Aortic stiffness, which occurs when the fibres in the arterial wall begin to fray under mechanical use, has been found to be a strong indicator of cardiovascular health and the risk of heart disease.

“This is the first study to assess the effects of aerobic exercise training with and without reducing calories on aortic stiffness, which was measured via cardiovascular magnetic resonance imaging (CMR) to obtain detailed images of the aorta,” said Tina E. Brinkley, lead author of the study and associate professor of gerontology and geriatric medicine at the Sticht Center for Healthy Aging and Alzheimer’s Prevention at the Wake Forest School of Medicine in Winston-Salem, North Carolina.

“We sought to determine whether adding caloric restriction for weight loss would lead to greater improvements in vascular health compared to aerobic exercise alone in older adults with obesity.”

The study employed a randomized controlled trial of 160 obese, sedentary adults, aged 65 to 79. The average age of the group, which was 74 per cent female and 73 per cent white, was 69 years. Subjects were randomly divided into three groups: Exercise plus regular diet, exercise plus moderate calorie restriction (250 calories per day) and exercise plus intensive calorie restriction (600 calories per day). Meals were prepared by a dietician and subjects received supervised exercise instruction four times a week for 20 weeks.

Cardiovascular magnetic resonance imaging was used to assess the structure and function of participating aortas and measure two other components of heart health: aortic arch pulse wave velocity (PMV) — the speed at which blood moves through the aorta — and distensibility, or the aorta’s ability to expand and contract. Higher values for PWV and lower values for distensibility are indicators of stiffer aortas.

Over the five-month period of the study, researchers found a 10 per cent decrease in body weight (experienced only by the group with a moderate cut to calories) was associated with significant improvements in aortic stiffness. This group enjoyed a 21 per cent increase in distensibility and an eight per cent drop in PWV. The other two groups experienced no significant changes to aortic stiffness.

Other health benefits — such as changes to BMI, total fat mass, abdominal fat, waist circumference and the percentage of body fat — were greater in the calorie-reduced groups than the exercise only group. Interestingly, weight loss in the two calorie restricted groups was found to be very similar despite almost twice the number of calories having been cut from the more restrictive group.

“Our findings indicate that lifestyle changes designed to increase aerobic activity and moderately decrease daily calorie intake may help to reduce aortic stiffness and improve overall vascular health,” Brinkley said. “However, we were surprised to find that the group that reduced their calorie intake the most did not have any improvements in aortic stiffness, even though they had similar decreases in body weight and blood pressure as the participants with moderate calorie restriction.

“These results suggest that combining exercise with modest calorie restriction — as opposed to more intensive calorie restriction or no-calorie restriction — likely maximizes the benefits on vascular health, while also optimizing weight loss and improvements in body composition and body fat distribution. The finding that higher-intensity calorie restriction may not be necessary or advised has important implications for weight loss recommendations to improve cardiovascular disease risk in older adults with obesity.”

Dave Yasvinski is a writer


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