Protein has been shown to benefit people in a number of different ways, from increasing metabolism (thermogenic effects) to de-greasing and repairing a fatty liver. One of the important benefits that increasing your dietary protein seems to deliver is the benefit of increasing lean muscle mass. Even in a calorie deficit, it has been suggested that increasing your protein will preserve your lean muscle so that the majority of weight will be lost from fat. You see when you go on a diet, eating less than your body needs, then “what” you are eating will result in you losing certain amount of muscle and a certain amount of fat.
An ideal diet, has you burning the greatest amount of fat, but preserves as much lean muscle as possible. Many people go on diets eating anything that they want (including junk food) but just less of it. What they do not understand is that they could be losing as much if not more muscle than fat, a fact that they will not be aware of simply by looking at the scale. Do you think that that would make a difference in your body composition and how you looked? Imagine if you were to lose 50 pounds of weight, but in one scenario you lost 50 pounds of fat compared to another scenario where you lost 25 pounds of fat and 25 pounds of muscle? Which scenario would you prefer?
A study that was just conducted this year, looked at the effects of dietary protein content on weight gain, energy expenditure and body composition during overeating. This was an excellent study because it was all performed in a controlled setting. This means that all the participants were observed, monitored and fed under the control of the researchers. Basically they were under house arrest for the duration of the study so all food eating was accurately recorded.
The results were interesting. This was an overfeeding study so all subjects, who were between the ages of 18 and 35, were fed more than their daily energy needs. One group was fed a calorie surplus that had 5% protein (low group), another had 15% protein (normal group) and the last group was fed a diet that had 25% of its calories coming from protein (high protein group). All groups were overfed an average of a thousand calories over their daily requirements.
The results proved that you can gain weight regardless of the macronutrient profile, of course. But it also proved that the higher the protein intake the greater the acceleration of fat burning and the increase in lean muscle mass. The low protein group gained the least amount of weight, the normal protein group gained more weight, and the high protein group gained the most. But, the interesting thing is that all 3 groups had gained the same amount of fat.
- The low protein group experienced no increase in energy expenditure (thermogenesis) and no increases in lean muscle mass.
- The normal group had an increase both in lean muscle mass and energy expenditure.
- The high group had even a greater increase in both!
The bottom line just looking at calories is that eating more than your body needs will increase your weight.
But, more importantly, this study proves the benefit of protein as it relates to thermogenic properties and retaining or increasing lean muscle even in a calorie deficit diet! Said differently if you want to have the body of your dreams it involves losing fat and retaining or increasing your lean muscle. To do that protein in the right amounts are key.
1)Bray, GA. Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial. JAMA 2012