Thursday, July 17, 2008

Diet Wars - Low Carb Wins

The confusion about which diet is best for health and weight maintenance has plagued us for decades. The New England Journal of Medicine reported today that the Mediterranean and low carbohydrate diets are the way to go. Here were the parameters:

Low Fat Diet - based on the American Heart Association with no more than 35% of calories from fat. The participants were counseled to consume low fat grains, vegies, fruits and legumes and to limit additional fats, sweets and high-fat snacks. Calorie restriction of 1500/day for women and 1800/day for men.

Mediterranean Diet- Rich in vegies and low in red meat with poultry and fish replacing beef and lamb. No more than 35% of calories from fat and the main sources of added fat were olive oil and 5-7 nuts a day. Calorie restriction of 1500/day for women and 1800/day for men.

Low-Carbohydrate Diet- 20g of carbs/day for 2 months with a gradual increase to a max of 120g a day. The intakes of total calories, protein and fat were not limited but the participants were counseled to choose vegetarian sources of fat and protein with no trans fat. (Based on Atkins diet)

All the groups lost weight but the low carb and Mediterranean diet groups lost the most. All groups decreased their waist circumference and blood pressure.

The low-carb group had the best lipid profiles (cholesterol and triglycerides) and the largest decrease in these levels.

C-reactive protein decreased the most in the Mediterranean diet and low carb groups.

The Mediterranean diet group had the best improvement with diabetes. The low fat group increased their fasting glucose levels. The low carbohydrate group had the best improvement in glycated hemoglobin (a marker for blood sugar control).

The liver tests were the same in all groups.

So the take home message is that calorie restriction works for weight loss (surprise) but the low carb and Mediterranean diets had beneficial metabolic effects beyond weight loss. Weight loss was the same with the low carb group without restricting calories!

It looks like the "Atkins Diet" might be making a comeback based on this well controlled trial.


Robin Plan said...

I was still surprised that the people in this study only lost 7.3, 10 or 12 pounds over 2 years.

Anonymous said...

What if people have a medium or bigger goal to lose then 12 lbs.?
I guess the South Beach Diet would be in the same catagory of Atkins or Low Carb.

Barbara K. said...

Did any of this research factor in regular aerobic exercise and it's impact not just on calories but on metabolism?

Toni Brayer MD said...

Anon: South Beach Diet is very similar to Atkins. A bigger goal would require both diet and exercise and really sticking with it.

barbarak: This study did not look at metabolism nor was there a formal exercise component.

Anonymous said...

How is getting over a third of your calories from fat "low fat"?

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