Dieters on the Mediterranean diet saw the best improvements in blood sugar levels. The diet wars are heating up once more after a new report by Israeli researchers suggests that low-carbohydrate and Mediterranean diets may be safer and more effective for weight loss than standard, medically prescribed low-fat diets.
In a two-year study, researchers from Ben Gurion University of the Negev (BGU), found that dieters don't always have to give up fats if they want to lose weight or increase health benefits, but instead can opt for diets that are low in carbohydrates like bread and pasta, or rich in fruits, healthy fats, and vegetables.
In the study, which was published in the New England Journal of Medicine, researchers monitored 322 moderately obese people who were assigned one of three diet regimes - a low-fat diet, a Mediterranean diet, or a low-carbohydrate diet like that popularized by Atkins.
Low carb dieters lose the most
Although all of the participants decreased the number of calories they consumed by similar amounts, those on the low-carb diet lost the most: 10.3 lbs. after one year, compared to 10 lbs for those on the Mediterranean diet in the same period, or just 6.5 lbs. for those on the low-fat diet.
"These weight reduction rates are comparable to results from physician-prescribed weight loss medications," explains Dr. Iris Shai, the lead researcher, from the S. Daniel Abraham International Center for Health and Nutrition in the Department of Epidemiology at BGU.
Moreover, the researchers found that the low-fat diet gave the least health benefits to dieters, compared with the Mediterranean and low-carb diets. Subjects on the Mediterranean diet saw the best improvement in blood sugar levels, while those on low-carb diets saw the biggest improvement in cholesterol levels.
Among diabetic participants, the standard low-fat diet actually increased the fasting glucose levels by 12mg/dL, while the Mediterranean diet induced a decrease in fasting glucose levels by 33mg/dL.
"Clearly, there is not one diet that is ideal for everyone," says Dr. Shai, who conceived the study with Dr. Stampfer, the senior author, while she was a Fulbright fellow at Harvard School of Public Health and Channing Laboratory in Boston, Massachusetts.
"We believe that this study will open clinical medicine to considering low-carb and Mediterranean diets as safe effective alternatives for patients, based on personal preference and the medical goals set for such intervention," she adds.
Trial at Dimona
The trial was conducted at the Nuclear Research Center in Dimona, Israel, in collaboration with Harvard University, the University of Leipzig, Germany and the University of Western Ontario, Canada. What is remarkable about the study is not only the relatively large number of participants, but that such a large proportion of them - 85 percent - stuck with the diet for two years.
This was partly achieved because of the significant cooperation between staff, subjects and their spouses involved in the study. The cafeterias at the isolated Dimona center went through a "health revolution," to provide healthy dishes that would fit each one of the dietary arms, and every day, foods for each diet were labeled with colored dots.
Dieters were given additional nutritional counseling, and counseled on how to stick to eating plans at home.
"The improvement in levels of some biomarkers continued until the 24-month point, although maximum weight loss was achieved by six months," says Dr. Shai. "This suggests that healthy diet has beneficial effects beyond weight loss."