Although some nutritionists downplay the notion that eating a certain combinations of protein, fat, and carbohydrates will result in insulin control and weight loss, a study presented at the American Heart Association's annual conference earlier this month seems to show otherwise.
Australian researcher Peter Clifton, MD, PhD, presented data from a 12-week study of 49 obese men and women with insulin resistance syndrome, a condition that leaves the body with too much circulating insulin (hyperinsulinemia). Insulin resistance syndrome, sometimes called Syndrome X, has recently been linked to obesity, and is estimated to affect more than 60 million people in the U.S.
The researchers wanted to determine if a high-protein weight-loss diet (30% of calories from protein), compared to a lower-protein weight-loss diet (15% of calories from protein), was more effective in reducing the components of insulin resistance syndrome. Even though there was no difference in the amount of weight loss between the two groups after 12 weeks, the results show improved insulin sensitivity with a high-protein diet -- and the numbers were most significant in men.
Despite the promising results, Clinton doesn't think clinicians should encourage their patients who have insulin resistance syndrome to embark on high-protein diets. "We need to wait for good data to show that's the way we should go," he tells WebMD. "At this point, we aren't sure about the long-term problems with [protein] diets. I know that high-protein diets are hard to achieve over the long term. ... So while it's possible our theory might be right, we certainly want to confirm it in a much larger study."
Others remain convinced that it's the calories that count. "Generally, what we do know is that it's calories that count in weight management, not necessarily hormonal responses to energy sources," Jennifer Nelson, MS, RD, tells WebMD. Nelson is the director of clinical dietetics at the Mayo Clinic in Rochester, Minn. "Because there is so little research on this, we can't substantiate those claims. Those claims are unverified."
Somewhat similar to the Zone diet is the so-called "Mayo Clinic" diet. But dieters beware!