Why macronutrient composition as well as calorie matter when trying to lose fat
Here’s another example of how it’s not just your caloric intake that matters when trying to lose fat, but also the macronutrient composition of those calories matter too. See below for more.
In a 2013 study published in the Federation of American Societies for Experimental Biology (FASEB) Journal, 39 recreationally-fit adults were split into three groups. Each group was put on a calorie-reduced diet for 3 weeks with their calorie intake being restricted by 30% and physical activity being increased by 10% for a 40% deficit in energy.
The difference between groups was that one group consumed the recommended dietary allowance (RDA) for protein, which is 0.36 g/lbs. per day. That’s about 64.8 grams of protein for a man who weighs 180 pounds. The second group consumed twice the RDA (0.72 g/lbs. per day), while the third group consumed three times the RDA (1.09 g/lbs. per day). In all three groups, dietary fat made up 30% of their diet with carbohydrates making up the remainder of the calories. Additionally, all groups followed a cardio- and weight-training program, but it was relatively mild.
The results showed that all three groups lost around the same amount of body weight. However, the groups who consumed double and triple the RDA for protein lost more fat and less muscle mass.
What’s interesting is that there wasn’t much of a difference in fat and muscle mass between the groups who ate two and three times more protein. That being said, it would be interesting to see if a more strenuous workout would favour the higher protein intake (3X the RDA). Regardless, the take-home message is clear – if you’re looking to lose fat and preserve muscle while dieting then you may want to go with a higher protein intake. However, there comes a point where more isn’t necessarily better and you need to find the amount that works best for you.
For more information:
Pasiakos, SM et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 2013. Sep;27(9):3837-47.