July 22, 2008

Mediterranean and Low-Carb Better than Low-Fat Diets

People following a Mediterranean or a low-carbohydrate (low-carb) diet had greater weight loss and improvements in blood sugar or cholesterol levels after two years than people on a low-fat diet, according to research published in the July 17 issue of the New England Journal of Medicine. These new study results follow on the heels of a recent AIDSmeds special report regarding low-fat, low-carb and Mediterranean diets in HIV-positive people.

The Mediterranean diet has been growing in popularity among nutritionists and physicians. It calls for limiting unhealthy fats from red meat and dairy and increasing healthy fats from olive oil and nuts, along with whole grains and lots of fresh vegetables and fruits. The diet has not, however, been well studied in comparison with both low-fat and low-carb diets.

To determine the relative virtues and disadvantages of each diet, Iris Shai, RD, PhD, of the Ben-Gurion University of the Negev, in Beer-Sheva, Israel, and her colleagues enrolled 322 moderately obese HIV-negative volunteers into the Dietary Intervention Randomized Controlled Trial (DIRECT). Participants were randomized to follow a Mediterranean, low-fat or low-carb diet for two years. People following the Mediterranean and low-fat diets had restrictions on the total amount of calories that were allowed each day, while people following the low-carb diet had no calorie restrictions.

Ninety-five percent of the study volunteers reported that they were adhering well to their diets after one year. This fell to 85 percent at two years. As with many diet studies, the greatest weight loss, on average, occurred during the first six to eight months of the study; the participants’ weights then rose again somewhat before stabilizing about 18 months into the study. After two years, the mean weight loss was 6.4 pounds in those following the low-fat diet, 10.4 pounds in those on the low-carb diet and 9.7 pounds in those on the Mediterranean diet.

All three diets lead to reductions in waist circumference and blood pressure. In terms of cholesterol, Shai’s team found that volunteers following a low-carb diet had the greatest increase in HDL, the “good” cholesterol, and drops in triglycerides. Thirty-six diabetics were in the study, and only those following the Mediterranean diet had improvements in blood sugar control.

While the study was not conducted in people living with HIV, the findings are similar to recommendations by many nutritionists experienced in treating HIV and lipodystrophy, a highlight of an AIDSmeds special report published in April.

Search: Mediterranean diet, carbohydrate, low-carb, low-fat, cholesterol, diabetes, Iris Shai, Benp-Gurion University, DIRECT

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