A recent study in the New England Journal of Medicine came to the conclusion that “Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.” That is, in the long term it doesn’t really matter whether a diet is high fat or low fat for the purpose of losing weight, as long as it has reduced calories. The obvious conclusion is that the right weight loss plan for any given person is the one they will actually follow long term.

It is worth noting several things about this study. First, they did find that those who attended regular counseling sessions lost more weight than those who didn’t. Clearly having support in weight loss efforts is important — even if it’s from relative strangers.

Second, all participants were given a modest physical activity goal of 90 minutes of moderate exercise per week. Compliance was self-reported. This works out to only 3 half-hour workouts per week. While this may be a great goal for sedentary people to reach within a few months, this was a 2 year study! The American College of Sports Medicine recommends that sort of workout 5 days per week. So do the United States Department of Health and Human Services and the CDC.

Finally, the lowest carbohydrate diet considered in this study was 35% of total calories from carbohydrates. On a 1500 calorie per day diet, that would work out to 131 grams of carbs daily. No traditional low-carb diet allows that much, except perhaps in the weight maintenance phase. Atkins followers begin the program at 20 grams per day (those on Protein Power get to exclude fiber from the carb count) and add more when they are close to reaching their weight loss goal. The medical community is generally down on true low-carb diets and the exercise community feels that you can’t adequately exercise on them, which is probably why they weren’t considered. However, the fact is that the results on this study are going to be misinterpreted as having compared a low-carb diet to a low fat diet when it did no such thing.

The bottom line is that successful and lasting weight loss depend on reducing calories, increasing activity, finding support wherever it exists, and sticking to the plan.