Many “experts” tell you to increase or decrease a specific macronutrient: fat, carbohydrates or protein, in order to lose weight. Low-fat, Low-carb, high-protein diets are all very common. But does it make sense to pay attention to macronutrients when you’re trying to lose weight?
One study placed 811 participants on 1 of 4 diets that varied in macronutrient content and tracked their weight loss (and other measures) for 2 years. Fat content was either 20% or 40%; protein content was either 15% or 25%; carbohydrate content was between 35% and 65%. Each group was instructed to reduce calories by 750 from their baseline. After 2 years, the participants’ weight had dropped in each group by a similar amount (an average of 8.8 lbs). The high protein group did lose 1.3 lbs more on average. The 35% carb group also lost 1.1 lbs more on average than the 65% carb group. There was no difference between the low-fat and high fat groups.
All groups improved risk factors for cardiovascular disease and diabetes. Low-fat and high-carb diets reduced LDL cholesterol (bad cholesterol) the most. Low-carb diets increased HDL cholesterol (good cholesterol) the most. Improvements in blood pressure and triglyceride levels were similar for all groups. A bonus finding was that weight loss counseling session attendance was highly correlated with weight loss in all 4 groups (although this could just be a measure of commitment level).
You can lose weight on diets with a wide range of fat, protein and carbohydrate content (as long as you reduce calories). All of these diets also improve risk factors for cardiovascular disease and diabetes. If you looking for an extra edge, low-carb, high protein diets appear to be slightly better for weight loss.
Sacks, Frank M., et al. “Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates.” New England Journal of Medicine 360.9 (2009): 859-873.