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To learn more from Dr. Jonny Bowden, we recommend When to Eat.
Q: I heard there’s a new study out on low-fat vs. low-carb diets. What’s the scoop?
You heard right. The study, published in the August 2010 issue of the Annals of Internal Medicine, was designed to test the effects of two years on either a low-fat or low-carb diet combined with behavioral counseling. Here’s what happened.
Researchers took 307 overweight participants (average body mass index [BMI] of 36) and divided them into two groups. The first group was put on a classic Atkins diet: only 20 grams of carbohydrates a day for three months, all of which came from fibrous vegetables. After three months, the Atkins (low-carb) group reintroduced five grams of carbs per day each week until their weight was stabilized. Participants had no restrictions on calories and could eat as much protein and fat as they liked.
The second group went on a standard low-fat diet, consuming between 1,200 and 1,800 calories a day with 30 percent or less of those calories coming from fat.
After 12 months, both groups lost approximately the same amount of weight (11 kilograms, or roughly 24 pounds). Both groups regained some weight during the second year, with no significant difference between the two groups. The average weight loss after two years was seven kilograms (about 15.5 pounds). As with most diet studies, some folks regain part of the weight they lose not because the diets don’t work but because people start drifting back to their old habits.
Though the media reported “no difference” between the two diets, several pieces of crucial information were left out. While weight loss was similar, the low-carb group had better cardiovascular results. At the end of six months, the low-carb group had lower triglycerides, lower VLDL (very low density lipoprotein) cholesterol and lower diastolic blood pressure. These differences between the diet groups equaled out by the end of the study, but one important difference that did not even out was HDL (“good”) cholesterol. The low-carb group had significantly higher (23 percent higher, to be exact) HDL cholesterol throughout the entire two years of the study.
According to the researchers, the behavioral counseling part of the program was as important to weight loss success as the particular diet. I tend to agree. The best diet is the one you stick with and the one you have support in doing. We recommend a healthy lifestyle approach to eating that the whole family can partake in. And if you follow the clean-eating approach, you’ll be a winner long term.