Led by Cara Ebbeling, the researchers set out to compare the efficacy of a low-glycemic-load diet in lowering the risk of obese young adults developing cardiovascular disease with that of a low-fat diet.
The results, published in the current issue of the American Journal of Clinical Nutrition, indicate that that the low-g diet may well be the best course of action for obese people who are concerned about the health implications of their condition.
Over a 12-month period, 23 obese young adults ate either an 'experimental' or a 'conventional' diet.
Those adhering to the experimental diet were permitted to eat foods with a low-glycemic index without strict limitation, with 45-50 percent of energy derived from carbohydrates and 30-35 percent from fat.
The conventional diet group's energy intake was restricted to 250 to 500 calories a day deficit, with fat comprising less than 30 percent of energy and carbohydrate between 55 and 60 percent.
Both groups experienced a significant decrease in body weight at six months, 8.4 percent and 7.8 percent respectively, which was largely maintained throughout the rest of the year.
Changes in cholesterol concentrations, blood pressure, and insulin sensitivity did not differ significantly between the groups.
But in the experimental group plasma triacylglycerols, fatty acid molecules associated with ischemic heart disease, decreased by 37.2 percent compared to 19.1 percent in the conventional group.
Mean plasminogen activator inhibitor 1 concentrations also decreased in the experimental diet group by 39 percent but increased 33.1 percent in the conventional diet group.
Plasminogen Activator Inhibitor-1 inhibits fibrinolysis, the process whereby fibrin clots produced by coagulation are broken down. The suppression of fibrinolysis increases the risk of arterial and venous thrombosis.
The low-glycemic-load diet reduces carbohydrates that are rapidly digested and that raise blood sugar and insulin to high levels, such as white bread, refined breakfast cereals, and concentrated sugars. Instead, it emphasizes carbohydrates that release sugar more slowly, including whole grains, most fruits, vegetables, nuts, and legumes.
The latest research builds on evidence amassed by more than 300 papers investigating the approach and the impact on it may have on obesity and obesity-related conditions in the last 18 months.
These include a Harvard University study published in the Journal of the American Medical Association last November, which drew similar conclusions to that of Ebbeling's team as to the potential for the low-glycemic diet to improve cardiovascular risk factors to a greater extent than the low-fat diet.
It also suggested that low-glycemic diets may have a lesser effect on lowering metabolism than low-fat diets, making dieters feel less tired, cold and hungry and more likely to stick to the regime long-term.