Wednesday, October 28, 2009

Choose Your Diet

A Mediterranean or low-carb diet may boost weight loss, but neither makes fat melt away. Israeli researchers assigned 277 men and 45 women, all middle-aged and obese (they averaged about 200 pounds), to one of three diets:

• The (so-called) low-fat diet cut calories (to 1,500 for women and 1,800 for men) and limited fat to 30 percent of calories (what most people were eating when they entered the study). Dieters were told to eat more fruits, vegetables, and beans and to cut back on fats and sweets.

• The Mediterranean diet cut calories (to 1,500 for women and 1,800 for men) and allowed more fat (35 percent of calories), mostly from olive oil (2 to 3 tablespoons per day) and nuts (5 to 7 per day). Dieters were told to eat more vegetables, poultry, and fish.

• The low-carb diet didn't cut calories or fat, but limited carbs to 20 grams a day for two months and 120 grams a day afterwards. Unlike an Atkins diet, dieters were told to get their fat and protein from plants, not animals.

After two years, those on the "low-fat" diet had lost an average of about 6 pounds,
while those on the Mediterranean or low-carb diet had lost an average of 10 pounds. The researchers noted that the 45 women in the study "tended to lose more weight on the Mediterranean diet," but they gave no further details.

Also, HDL ("good") cholesterol rose more on the low-carb diet and triglycerides (which are bad) dropped more on the Mediterranean and low-carb diets. Among the 36 participants with diabetes, fasting blood sugar levels were lowest on the Mediterranean diet.

What to do: For men, the best diet might be either low-carb or Mediterranean, but
women and anyone with diabetes might do better with a Mediterranean diet.

To go Mediterranean, load your plate with fruits and vegetables, but leave some room for whole grains, nuts, poultry, and seafood. (Meat-and-cheese-laden pizza, lasagna, and similar Italian dishes have too much saturated fat to fit in a traditional Mediterranean diet.) A tablespoon of olive oil (or any oil) has 120 calories, so don't go beyond 2 or 3 tablespoons a day.


All fish are not equal when it comes to omega-3 fats like EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Researchers analyzed samples of 30 species
of fish caught or farmed in the United States, Ecuador, Honduras, Norway, New
Zealand, Canada, or Chile. Their goal was to find fish with the most EPA and DHA, but the lowest levels of an omega-6 fat called arachidonic acid, which may promote inflammation.

Among wild-caught fish, salmon was highest in omega-3s. Other wild fish had less, but none were high in arachidonic acid.

Farmed salmon and trout were higher in arachidonic acid than wild-caught fish, but
they also had high levels of omega-3 fats to balance their arachidonic acid, in contrast, farmed tilapia and farmed catfish had more arachidonic acid.

What to do: It's still uncertain if arachidonic acid is harmful, but if you're looking for omega-3s, you may be safer with either wild or farmed salmon or trout than farmed tilapia or catfish.

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