Obese and overweight individuals suffering from metabolic syndrome or Type 2 diabetes showed significant health improvements after only three weeks of diet and moderate exercise even though they remained overweight, according to a report to be published in the Journal of Applied Physiology.

"The study shows, contrary to common belief, that Type 2 diabetes and metabolic syndrome can be reversed solely through lifestyle changes," according to lead researcher Christian Roberts of UCLA.

The 21-day study, conducted at the Pritikin Longevity Center, involved 31 men, ranging in age from 46 to 76, who ate a high-fiber, low-fat diet with no limit to the number of calories they could consume. The participants also did 45-60 minutes of aerobic exercise per day on a treadmill.

Fifteen of the men had metabolic syndrome, a condition that is characterized by excessive abdominal fat, insulin resistance, and blood fat disorders such as high levels of triglycerides or low levels of HDL ("good") cholesterol). Thirteen of the participants had Type 2 diabetes. Some participants had neither metabolic syndrome nor diabetes , but were overweight or obese.

"This regimen reversed a clinical diagnosis of Type 2 diabetes or metabolic syndrome in about half the participants who had either of those conditions. However, the regimen may not have reversed damage such as plaque development in the arteries," Roberts said.

"However, if Type 2 diabetes and metabolic syndrome continue to be controlled, further damage would likely be minimized and it's plausible that continuing to follow the program long-term may result in reversal of atherosclerosis.

"The results are all the more interesting because the changes occurred in the absence of major weight loss, challenging the commonly held belief that individuals must normalize their weight before achieving health benefits," Roberts said. Participants did lose two to three pounds per week, but they were still obese after the 3-week study.

Other sources: American Physiological Society