The study, published in the Journal of the American College of Cardiology, lasted two years and showed heart and vascular health improvements in four areas after weight loss: decreased carotid artery wall thickness, decreased thickness of heart muscle, and improved pumping function and relaxation function. These are key measures of heart health, and problems can lead to heart failure and plaque formation in artery walls.
The 60 participants ranged in age from 22 to 64 and were moderately obese. They were put on a low-calorie diet of 1200 to 150 for women and 1500 to 1800 for men, and were randomly assigned to low-fat or low-carbohydrate diets. They were also instructed to exercise for 3.5 hours per week. Forty-six participants completed the entire two-year follow-up period. They lost an average of 22 pounds or 9 percent of their body weight. The greatest improvements in cardiovascular health were seen six to 12 months into the study. After 6 months, the participants began to slowly regain the weight they had lost, and they ended up averaging 9 pounds below their original weight after two years. However, they still retained some of the cardiovascular benefits they had gained during the first year. Interestingly, both the low-fat and the low-carb groups lost similar amounts of weight and gained similar amounts of cardiovascular benefit.
"Losing 20 or so pounds might seem daunting to some people, but we showed that even a more modest weight loss can yield heart and vascular benefits," says first author Lisa de las Fuentes, M.D., a Washington University heart specialist at Barnes-Jewish Hospital and assistant professor of medicine in the Cardiovascular Division at the School of Medicine. "It's important to realize that you can choose goals that are attainable and work progressively toward them. You don't necessarily need to lose 50 pounds to improve your heart function."
The researchers used new technologies in echocardiography and ultrasound imaging to assess the participants’ cardiovascular health. They were able to detect modest heart dysfunction at the beginning of the study, based on thickened heart muscle, abnormal pumping and relaxation, and thickened artery walls. Six to 12 months into the study, all of these measures had become significantly improved.
De la Fuentes notes that the study is important because none of the participants were heavy enough to qualify for gastric bypass surgery, so it’s important to demonstrate the health benefits of diet and exercise programs to achieve moderate weight loss.
