Eliminating Just 200 Calories Per Day Could Pay Major Dividends for Heart Health in Obesity

Tina Brinkley, PhD

Underscoring the impact of even the smallest lifestyle changes on disease course, a new study from the Sticht Center for Healthy Aging and Alzheimer’s Prevention at Wake Forest School of Medicine found cutting 200 calories per day could have a major impact on aortic stiffness in older adults with obesity.

The first study to assess the effects of aerobic exercise training with and without caloric restriction on changes in proximal aortic stiffness using CMRI, results indicate exercise alone had minimal effects but was associated with increased distensibility and decreased pulse wave velocity when combined with caloric restriction.

“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,” said lead investigator Tina Brinkley, PhD, Associate Professor of gerontology and geriatric medicine at the Sticht Center for Healthy Aging and Alzheimer’s Prevention at Wake Forest School of Medicine, in a statement. “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.”

With the growing burden of obesity becoming more apparent and the need for mitigation strategies to address this increased burden, Brinkley and a team of colleagues from Wake Forest School of Medicine designed the current study to learn more about the impact of aerobic exercise with and without caloric restriction in older patients with obesity. To do so, investigators designed the current study as an ancillary study to the INFINITE (Investigating Fitness Interventions in the Elderly) trial, which was a 20-week, 3-arm randomized controlled trial with 180 participants.

Participants included in the trial were randomized to 1 of 3 interventions for 20 weeks. Ultimately, 56 patients were randomized to exercise only, 49 were randomized to exercise plus moderate caloric restriction, and 55 were randomized to exercise plus high caloric restriction. Among those randomized to caloric restriction, those in the moderate group experienced a reduction of approximately 200 calories per day and the more intensive restriction group experienced a reduction of approximately 600 calories per day.

For the purpose of analysis, participants walked on a treadmill 4 days per week for 20 weeks while under the supervision of 2 interventionists to ensure similar exercise stimulus was achieved across the study groups. Total duration of exercise progressed from 15-20 minutes at 50% heart rate reserve during the first week of training to 30 minutes at 65-75% heart rate reserve by the sixth week of training.

Participants randomized to the exercise-only arm were instructed to adhere to their regular dietary intake during the study. Those randomized to caloric restriction plus exercise were provided 2 meals per day and picked up their food 3 times per week. Of note, these patients were responsible for preparing their own breakfast meal according to an approved menu provided by a dietitian and were instructed to keep a log of everything they consumed.

The primary outcomes of interest were changes in aortic pulse wave velocity, and aortic distensibility, as well as other measures of aortic structure and function. CMR assessments were conducted using a 1.5T Siemens Avanto scanner.

Upon analysis, results demonstrated weight loss was significantly greater in the exercise plus moderate caloric restriction (-8.0 kg [95% CI, -9.17 to -6.87]) and the group with more intensive caloric restriction (-8.98 kg [95% CI, -10.23 to -7.73]) compared to the exercise-only group (-1.66 kg [95% CI, -2.94 to -0.38]; P <.017 for both). Investigators pointed out significant treatment effects were observed for descending aorta distensibility (P=.008) and strain (P=.004) as well as aortic arch pulse wave velocity (P=.01). In the moderate restriction plus exercise group, investigators noted a 21% increase in distensibility (P=.016) and an 8% decrease in pulse wave velocity (P=.058) compared to exercise alone.

Further analysis indicated there were no significant differences in any of the measures of aortic stiffness in the exercise-only or the more intensive caloric restriction group. Additionally, there were no significant changes in any other measure of aortic structure or function among these groups. Investigators also pointed out increases in distensibility were correlated with improvements in body weight and body fat distribution, but these associations did not reach statistical significance after adjustment for confounding factors.

“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.”

This study, “Effects of Exercise and Weight Loss on Proximal Aortic Stiffness in Older Adults With Obesity,” was published in Circulation.