What a High Protein Diet Can and Can't Do
If you’ve ever googled the word diet, you’ve likely run into the suggestion that changes to your protein intake can help you lose weight. Whether it’s tweaking percentages of macronutrients, increasing grams per meal, or incorporating certain high protein foods, some advice gets quite complicated. But there’s an important stipulation to factor in among all the buzz. New research goes beyond the scale and helps explain what protein can and can’t do. The findings have implications for dieters you may not have expected.
Calories In - Fat On
The study tested the effects of a low, normal, and high-protein diet of 25 participants. Though small, the study is notable in nutrition research because participants lived in a controlled inpatient metabolic unit for up to 3 months where all their meals were observed by dietary staff. Researchers, led by George A. Bray, MD of Pennington Biomedical Research Center, conducted a trial on healthy male and female participants who were fed 40% more calories than their weight maintenance levels. All participants stored the same amount of fat from the excess calories, about 7½ pounds. In a video summary of the study’s findings, Dr. Bray adds, “…there was no evidence that the low, normal, or high protein diet influenced the storage of calories as fat, only the amount of calories that were eaten.”
Lean Body Mass Loss
While participants gained virtually equal amounts of fat, those on the low-protein diet experienced an interesting result. On the low-protein diet (5% of daily calories) participants gained about half as much weight as their normal (15%) and high-protein (25%) counterparts: about 6 pounds vs. 13 pounds respectively. But don't go throwing out your Greek yogurt just yet. The difference was the result of a loss in lean body mass. This finding speaks to the importance of overall body composition, including body fat percentage. Healthy weight loss means losing pounds of fat, not muscle. Here, additional protein intake helped retain and gain lean body mass. In fact, the findings show the high protein group increased lean body mass at a higher rate than the normal protein group. The takeaway is to think fat loss, not weight loss. While a pound of muscle and a pound of fat are both a pound, muscle takes up less volume and helps maintain your strength and overall health. Excess body fat doesn't do that.
Burn Baby Burn
There’s another take away from the study in the way of resting energy expenditure (REE). This number represents between 65% and 75% of total daily calorie expenditure, the rest of which is determined by physical activity level and the calories it takes our body to process food. Those on the normal and high protein diets were found to have increased REE when compared to the low-protein group. Like lean body mass, protein intake mitigated the increase, with the high protein group showing a higher increase than the normal protein group.
While high-protein diets are said to burn more fat, the more accurate point suggested by this study is when compared to low protein diets, a higher percentage of protein in the diet, increases lean body mass retention and resting energy expenditure. However, when it comes to weight loss, as has been proven time and again, without a caloric deficit, the pounds won't come off. Dr. Bray sums up the study’s findings with this, “The key first message is to reinforce the widely held professional view that calories count…the storage of fat is directly related to the amount of extra calories you have eaten.” He adds, “Weight loss, like weight gain, is a direct function of the amount of calorie excess or surplus that you are exposing your body to.”
Where to Start
If you think you're not getting enough protein in your diet, you may be wrong. According to a separate study by University of Colorado researchers, the average American gets about 17% of their calories from protein each day. So, unless you are below the Institute of Medicine’s recommendation of between 10% to 35% of calories from protein daily, your protein intake may be normal. Increasing your protein intake may help you retain lean body mass and increase your REE, but the only way to lose fat is by keeping your calorie count in check.
List the percentage of calories from protein in your favorite foods? To get the number, multiply each gram of protein by 4 and divide that number by the total calorie count of the food.
27% of the 227 calories in a cup of black beans comes from protein
15.2 grams of protein per serving X 4 calories per gram = 60.8 protein calories 60.8/227 = .267 or 27% of calories from protein.