The Centers for Disease Control and Prevention reports that as of 2008, 68 percent of American adults older than the age of 20 are either overweight or obese. The quest for an effective and quick diet is a common cause among many of these individuals. Some health professionals recommend low-carbohydrate, high-protein diets as a way to quickly lose weight. Though the average weight loss on these diets can be substantial, research into the overall health benefits of high-protein diets is not conclusive. Always speak to a registered dietitian before undertaking any major weight-loss plan.
Short-Term Weight Loss
One of the main reasons that low-carbohydrate, high-protein diets have become popular is that some studies have shown them to produce faster weight loss in the short term than a traditional calorie-restriction diet. In her 2001 review of high-protein diet research for “The American Journal of Cardiology,” Dr. Margo Denke reports that a 500-calorie restriction with a nutrient balanced diet typically results in roughly a 1- to 2-pound weight loss each week. Meanwhile, the first week of a low-carbohydrate, high-protein diet with a 500-calorie restriction will yield an average weight loss of somewhere between 4.4 and 6.6 pound
The exceptionally high average weight loss during the first weeks of a high-protein diet are due to a loss of total body water weight rather than excess fat burning. Denke states that extra protein consumption beyond what your body requires mobilizes glycogen, or energy, stores in your body and generates ketone bodies, which are a water-soluble by-product of fat cell breakdown. Both of these metabolic processes cause your body to expel more water than normal, creating a greater weight loss. Registered dietitian Janice Hermann, Ph.D., states that weight loss through water weight is not sustainable on a high-protein diet, and continued weight-loss results in the long-term require you to consume fewer calories per day.
In 2009, the “New England Journal of Medicine” published one of the most substantial studies regarding average long-term weight loss on calorie-restricted diets with varying macronutrient composition. A total of 811 adults were randomly assigned either a low-carbohydrate and high-protein, high-fat and low-protein, low-carbohydrate and high-fat or balanced fat, protein and carbohydrate diet. At the end of two years, the 80 percent of subjects who completed the trial had an average weight loss of nearly 9 pounds across all of the different diet types. The researchers of the study concluded that calorie restriction leads to the same average weight loss over time, regardless of the composition of your diet.
Though low-carbohydrate, high-protein diets have been proven effective for weight loss, the Harvard School of Public Health reports that long-term side effects of such a diet are not known at this time. Excessive protein increases the amount of work your kidneys have to do and may decrease the amount of calcium you have. Additionally, high-protein diets may be high in unhealthy fats and low in essential nutrients due to a lack of fruits and vegetables.