A lot of powdered drinks and milkshakes out there--the ones that are packed with supplemental protein--are promising to help you feel fuller and lose weight. All you have to do is drink enough of them before and after meals to make sure you're all filled up, or so it seems.
But a new study has now shown that--when it comes to losing weight--a standard protein diet (in which protein supplies 17 percent of its calories) is just as effective as a high-protein diet (where protein supplies 35 percent of the calories).
Does consuming extra protein lead to weight loss?
The study, which was conducted over 12 weeks, recruited 56 middle-aged men with an average age of 45 years and an average body mass index (BMI) of 33.6 kg/m2 (the "mild obesity" category). The scientists randomized the subjects into 2 groups, and fed both groups a low-fat diet that supplied each man with about 1,700 calories a day. The 2 diets differed only in the amounts of protein and carbohydrates they provided:
The first group of men--let's call them the standard group--were provided with a standard-protein, higher-carbohydrate diet. Each day, the average subject in this group consumed about 1,700 calories, 84 grams of protein, 210 grams of carbohydrate, and 47 grams of fat.
The other half of the participants--we'll call them the higher-protein group--were given a high-protein, standard-carbohydrate diet. Each day, the average subject in this group consumed about 1,700 calories, 129 grams of protein, 154 grams of carbohydrate, and 49 grams of fat.
Summing Up the Two Test Diets
The scientists, who were led by researchers at the University of South Australia and Australia’s Commonwealth Scientific Industrial Research Organization, sought to compare the effects of 2 low-fat, low-calorie diets that differed only in their carbohydrate-to-protein ratios. The researchers focused on the 2 diets' effects on the weight, strength, and aerobic capacity of these 2 groups of overweight and obese men.
COMPARING THE 2 DIETS AT A GLANCE
Proteins, grams/day (percent of calories)
84 (17 )
The Study's Results (In Terms of Body Weight)
The study, which was published in the European Journal of Nutrition, concluded that, with regard to the amounts of weight lost, the subjects who ate the higher-protein, standard-carb diet did not fare any better than did those eating the standard-protein, higher-carb diet.
The Study's Results (In Terms of Strength, Endurance, and Eerobic Capacity)
The subjects in both groups recorded comparable scores with respect to their peak-oxygen uptake, peak-handgrip strength, and knee-extensor strength. The only difference found between the 2 groups was that the higher-protein group saw a slightly greater reduction in fat mass, but this difference was not statistically significant.
The scientists concluded that the aerobic capacity of these men was not affected by the protein-and-carbohydrate composition of one's diet, at least during calorie restriction with low-fat diets.
Studies show that most people consume far more protein than their bodies need.
As a general guideline for adults, the daily recommended dietary allowance (RDA) for protein is 0.8 grams for every kilogram of body weight. Therefore, an adult male weighing 220 pounds (99.8 kilos) might need no more than (0.8 x 99.8 = 79.84) 80 grams of protein per day. Some of the protein-supplement products being gobbled up by folks these days provide half this amount in just a single serving!
Consequently, the 129 grams of protein fed each day to the high-protein group in this study was probably excessive and unnecessary in terms of the average person.
This study was small, and looked at middle-aged men, so its results can’t be extrapolated to women, children, or adolescents.
It’s important to keep in mind that whenever you eat a serving of protein that's greater than what your body needs, you are not providing yourself with any additional benefits. And the fact is, excess protein can even work against your weight-management efforts.