A trainer at my gym says that eating a high-protein low-carb diet can help people lose fat and gain muscle simultaneously. Is that true?


High-protein low-carb diets have been used for years by bodybuilders to strip off bodyfat for contests. In recent years, high-protein low-carb diet plans have been popular in the United States; people who have tried them have had tremendous success in shedding pounds of bodyfat. Numerous current studies show that dieters who follow high-protein low-carb strategies — even plans with higher fat intake — lose more fat and maintain or gain more muscle mass than dieters who rely on higher carb diets.

Yes, you read that right —many dieters actually gained muscle mass without working out, simply by eating a high-protein diet. This is due to several factors. First, amino acids from protein drive muscle growth. When you consume a high-protein meal, amino acids from the protein travel to muscle cells and actually initiate the processes that cause muscle growth.

Second, high-protein low-carb dieters burn a lot of fat for fuel because carbohydrates, the other major fuel source, are in short supply on such plans. When fat is burned at high rates, it produces byproducts known as ketones. The body can use ketones as a fuel source, thus sparing muscle from being used for that purpose.

A British study reported that men who eat more protein and fat have higher insulin-like growth factor-I (IGF-I) levels than those who eat more carbs. IGF-I is a powerful growth factor that is similar to insulin (hence the name) and helps  growth hormone initiate a number of its anabolic processes, such as muscle growth. Foods that help raise IGF-I levels include red meat, such as steak and hamburger, pork, chicken, eggs and dairy products. Unfortunately, IGF-I appears to have a dark side. Researchers have connected high levels of IGF-I to an increased risk of certain cancers. As yet, little is  known about this side of IGF-I.

To get big and lean and still stay healthy, consume high-protein foods that help raise IGF-I levels, but also consume plenty of tomato products, such as tomato sauce, ketchup and salsa. Lycopene in tomatoes has been shown to prevent tumor growth stimulated by IGF-I.