Low-Carb Diets Combat Metabolic Syndrome

(Page 2)

And, Hayes said, "By the end of the study, about 50 percent no longer had metabolic syndrome."

The study participants didn't follow the diets strictly, he found. "Phase one intake was 25 percent [carbohydrates], on average," he said, rather than the 10 percent recommended. "Phase two carb intake was 35 percent," he said, although 27 percent was recommended. But it was a reduction from the participants' pre-study diet, which included 47 percent of calories from carbohydrates, he said.

To find out why the weight declined, Hayes' team did hormone assays, measuring fasting and post-meal blood levels of hormones associated with appetite and food intake, such as insulin, leptin and cholecystokinin (CCK).

"We found some changes in hormone levels," he said. "We saw a decrease in insulin, a decrease in leptin levels by the end of phase one. It was fast."

"By the end of phase 2, the insulin levels had crept up toward baseline; the leptin levels also rose, but it did not come back to the levels at baseline," Hayes said.

"These alternations in hormone levels acting together help reduce the amount of food consumed," he said. "There's a synergy. Based on the literature already out there, we are speculating that this synergy of hormones may be the mechanism explaining why people are satisfied with less food and [the low-carb diet] results in weight loss."

However, Hayes emphasized that the study, published in the August issue of The Journal of Nutrition, was small and preliminary, and more research is needed.

Connie Diekman, director of university nutrition at Washington University in St. Louis and president of the American Dietetic Association, also urged caution when interpreting the study findings. "The study is small in size, and the population is not extremely diverse," she said, although she thinks the study design was good.

"The study was focused on metabolic syndrome, so the outcomes may not be transferable to people who are overweight but do not have the syndrome, since the cause of the syndrome is still not clear," Diekman said.

More information

To learn more about metabolic syndrome, visit the American Heart Association.