The principles of energy balance is one of the first thing students learn in Nutrition: To lose weight, your energy intake must be less than your energy expenditure. Calories determine weight loss, not the type of calories you eat. Several well controlled studies showed people on low carbohydrate diets lose more weight than those on mixed or high carbohydrate diets. Was your nutrition teacher wrong? Does the composition of the diet matter when trying to lose weight? University of Wisconsin researchers reviewed six studies and found no difference in 24- hour energy expenditures in people on low, moderate and high carbohydrate diets. Proteins are made from amino acids that are converted by lever into blood sugar. Eating high protein helps maintain a steadier level of blood sugar so you don't get hungry as fast. Protein should contribute around 25 to 30 percent of your energy intake when you are trying to lose weight because it suppress hunger.