Some people lose excess fat on high protein diet than a substantial carb or high fat diet. It will take energy to digest sustenance. Consuming one gram of protein (5.65 calories) yields only 4.0 calories of energy. One gram of fats (9.4 calories) yields 8.9 calories of energy. One gram of carbohydrates (4.1 calories) yields 6.0 calories of energy. You lose nearly 30% of the energy when consuming protein, but only 7% from fat, and 2% from carbohydrates. This accounts approximately half the loss difference from people on a premier carb v. low carb diet.