BOSTON (Reuters) - A long-term study of three very different diets has concluded that all produce similar amounts of modest weight loss, although the health benefits of the three may vary.
After two years, dieters lost an average of 7.3 pounds (3.3 kg) on the low-fat regimen, 10 pounds (4.6 kg) on the Mediterranean diet and 12 pounds (5.5 kg) on a mostly vegetarian version of the low-carbohydrate Atkins diet, Israeli researchers reported on Wednesday.
More than 82 percent of the dieters were men, with an average starting weight of just over 200 pounds (90 kg).
“The good news is, we have alternatives,” said Iris Shai of Ben-Gurion University of the Negev, who led the study published in the New England Journal of Medicine.
“If we fail in one strategy, we may want to choose another diet. We cannot think any more that one diet fits all,” Shai added in a telephone interview. “This study will open clinical medicine to considering low-carb and Mediterranean diets as safe alternatives for patients.”
The amount of weight lost at the two-year mark was similar to the effects of some prescription diet drugs, she said.
The low-carbohydrate diet excelled at improving the cholesterol profile, reducing the total cholesterol-to-good cholesterol ratio by 20 percent, compared to just 12 percent in the low-fat diet. For diabetics, the Mediterranean diet was best for lowering fasting glucose levels.
“Women tended to lose more weight on the Mediterranean diet,” the researchers added.
Nearly 85 percent of the 322 moderately obese volunteers were sticking to their diets at the two-year mark, in part because the cafeteria at their workplace, the Nuclear Research Center in Israel, prepared healthy dishes for each group every day. Spouses were educated to help the participants at home.
Both the low-fat and Mediterranean diets restricted calories. The Mediterranean diet had the most dietary fiber and monounsaturated/saturated fat -- so-called healthful fats. The low-carb diet had the most fat, protein and dietary cholesterol.
“The low-fat, restricted-calorie diet was based on American Heart Association guidelines. We aimed at an energy intake of 1,500 calories per day for women and 1,800 calories per day for men, with 30 percent of calories from fat, 10 percent of calories from saturated fat, and an intake of 300 mg of cholesterol per day,” the researchers wrote.
“The participants were counseled to consume low-fat grains, vegetables, fruits, and legumes and to limit their consumption of additional fats, sweets and high-fat snacks.”
The Mediterranean diet also kept calories to 1,500 for women and 1,800 for men and it was rich in vegetables and low in red meat, with poultry and fish replacing beef and lamb, and fat coming from olive oil and a few nuts each day.
The low-carbohydrate diet was based on the Atkins diet, which does not limit calories but reduces intake of processed carbohydrates.
“However, the participants were counseled to choose vegetarian sources of fat and protein and to avoid trans fat,” the researchers wrote.
Editing by Maggie Fox and David Wiessler
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