Can a High-Protein Diet Help you Lose Weight?
Eight ways to pump up the protein in your diet
By Kathleen Zelman, MPH, RD/LD
Reviewed By Louise Chang, MD
Low-carb diets are last year's news, but high-protein is emerging as the latest buzz in weight control. That's because emerging research has hinted that protein may be able to satisfy hunger better than either fats or carbohydrates.
Could a high-protein diet really help you eat fewer calories (and thus lose weight) by keeping your hand out of the cookie jar? WebMD asked some experts for their views.
What Studies Show
Participants in a study recently published in the American Journal of Clinical Nutrition reported greater satisfaction, less hunger, and weight loss when fat was reduced to 20% of the total calories in their diets, protein was increased to 30%, and carbs accounted for 50%. The study participants ate some 441 fewer calories a day when they followed this high-protein diet and regulated their own calorie intake.
Another study, reported in the Journal of Nutrition, showed that a high-protein diet combined with exercise enhanced weight and fat loss and improved blood fat (lipid) levels.
"Our research suggests that higher-protein diets help people better control their appetites and calorie intake," says researcher Donald Layman, PhD, a professor at the University of Illinois at Urbana-Champaign.
"Diets higher in protein [and] moderate in carbs, along with a lifestyle of regular exercise ... have an excellent potential to reduce blood lipids [and] maintain lean tissue while burning fat for fuel without dieters being sidetracked with constant hunger."
Researchers don't understand exactly how protein works to turn down appetite. They surmise that it may be because a high-protein diet causes the brain to receive lower levels of appetite-stimulating hormones.
"We are not exactly sure of the mechanism for satiety, whether it is due to [eating] fewer carbs and/or the specific protein effect on hunger hormones and brain chemistry," Layman says.
And more research is needed before experts can make sweeping recommendations that people boost the protein in their diets, says American Dietetic Association president Rebecca Reeves, DrPH, RD, an obesity researcher at the Baylor College of Medicine.
"I think it is fascinating and intriguing, yet we need the evidence that higher-protein diets are more effective over the long term," Reeves says.
How Much Do You Need?
We need protein at all stages of life, for a variety of bodily functions. It's the major component of all cells, including muscle and bone. It's needed for growth, development, and immunity to fight off infections and protect the body.
The Institute of Health's Dietary Reference Intake (DRI) recommendations allow for a wide range of protein intake -- anywhere from 10% to 35% of total calories -- for normal, healthy adults. For example, on an 1,800 calorie diet, you could safely consume anywhere from 45 grams (that's 10% of calories) to 218 grams (35%) of protein per day.
However, the Recommended Dietary Allowance (RDA) for protein is 56 grams a day for men and 46 grams a day for women. Most Americans have no problem getting this much, but would struggle to take in enough protein to make up 35% of their calories.
That said, is it possible to eat too much protein?
"There are no dangers associated with higher intakes of protein -- unless you have kidney disease," says Layman.
To get the potential weight loss benefit, Layman advises aiming for around 120 grams of protein a day. "If you want to increase your protein intake, do it slowly over the course of a week," he recommends.
To be on the safe side, check with your doctor before adding large amounts of protein to your diet.
Controlling Your Appetite
In theory, losing weight is quite simple -- just eat less and exercise more -- but of course, putting it into practice can be complicated. Finding a diet with the right combination of nutrients, that you enjoy, and works with your lifestyle is a very individual process.
"Some people fare better on a high-carbohydrate, diet whereas others are hungry all the time on the same diet," Layman says.
And of course, if you're hungry all the time, eating fewer calories will be challenging.
For better appetite control, Reeves recommends dividing your daily calories into smaller meals or snacks and enjoying as many of them as possible early in the day, with dinner being the last meal.