Protein has been a shining star in the Nutrition Facts Panel because many consumers believe that consumption of protein can help one build muscle and also lose weight. So much so that weight conscious consumers often check the protein content before they purchase any food for their weight management diet.
Can getting more of your calories from protein really help one gain muscle mass or lose body fat?
According to researchers at Pennington Biomedical Research Center in Louisiana, it is the calories that matter.
Pennington researchers designed a well-controlled study of inactive subjects—25 men and women who consented to live in the laboratory and eat only what was served to them. The researchers first established the base caloric needs for each of the study subjects measuring the consumption and energy expenditure of the subjects during a two week period. The group was divided into three groups based on the amount of protein in their diets: 5 percent (low), 15 percent (medium), and 25 percent (high). For the next eight weeks, the subjects remained extremely sedentary—watching television and playing cards—and were allowed to exceed their basic caloric needs by about 1,000 calories a day.
As a result, regardless of the group, every study subject gained fat—about 7.5 to 8 pounds. The group that consumed the lowest amount of protein lost about 1.5 pounds of lean body mass while the mid- and high-protein subjects gained approximately 6 to 7 pounds of lean body mass. Lean body mass is defined as a combination of water, connective tissues, glands, and muscle—anything besides fat.
The lean body mass gains in the mid- and high-protein group are plausibly because of the additional protein in their diets. Subjects who consumed more protein burned significantly more calories because of the energy required to metabolize the additional protein. Yet, this additional energy expenditure did not affect the amount of fat gained by these groups compared to the low-protein group.
By measuring (versus estimating like many other studies) what the study subject ate, how much they ate, and how much energy they spent under controlled conditions, the study showed that the metabolic pathway to dispose of proteins is distinct and different from the metabolic controls on fat storage. Low protein diets are clearly not a good idea since they cause loss in muscle mass, but there is really no significant different between diets containing 15 percent protein or higher.
The bottom line is crystal clear. Overeating—regardless of what it may be—means excess calories which leads to excess fat.
The implications for product formulators are simple and clear: it is not the protein, fat, or carbohydrate content of your product that matters as much as how many calories you are packing into each bite. Pack more fiber or water and you can dilute the caloric content per bite or sip.
The results also suggest that high protein diets cannot help one lose weight, unless they also cut down calories.
Regardless of the source of protein—meat, dairy, eggs, or soy—it’s the calories that clearly matter!
Reading suggestion: Calorie Wars: Fat, Fact and Fiction. By Larry Deutsch, M.D. and Jeff Schweitzer, Ph.D. The book’s bold new message: CALORIES IN, CALORIES OUT. EVERYTHING ELSE YOU READ IS BUNK.