Protein For Weight Loss
Eating a high protein diet has also been linked with an increased ability to lose weight, using gluconeogenesis as the intermediary. It is crucial to note here that the high-protein diet referred to by the studies and this article is NOT an extremely high protein, high fat diet such as the Atkins diet, where fat can make up as many as 60% of the calories.
High-protein diets, as referred to by studies, usually means a diet composed of 25-30% protein, 40-45% carbohydrate, and 28-30% fat. This is still a very high protein diet, but it incorporates healthy amounts of carbohydrates and fats as well. Additionally, many studies note that protein should NEVER come at the expense of fruits and vegetables, all of which contain vastly more phytonutrients and micronutrients than most high-protein foods, including vegetarian ones (beans can’t replace greens!).
One of the key functions protein has on our appetite is to increase satiety, which means more protein makes you feel fuller, longer. More interesting, though, is the fact that when our body converts protein into glucose, it loses 33% of the energy available, meaning that for every 1 gram of protein converted, only .66 grams of glucose is made available. Protein and carbohydrates both have the same amount of energy per gram: 4 calories. When protein is converted via gluconeogenesis, the potential four calories of energy is reduced to only 2.66 calories. When a high protein diet is consumed, more energy must be taken from protein to account for the loss of energy from dietary fats and carbohydrates.
The end result is that when equivalent amounts of food are eaten from a high-protein and a low-protein diet, the high-protein diet fills you up more and creates less, but longer lasting and less likely to be stored energy. Fewer calories are available to turn into fat, and the increased protein supports lean muscle building as well, which when combined with exercise leads to increased muscle, which will further boost the resting metabolic rate of the body as a whole.
For the results to be most effective, protein is high, but carbohydrates must be high as well. Ingesting incredibly high amounts of protein in an attempt to force the body to supply all of its energy from gluconeogenesis, in the absence of carbohydrates, does not seem to work as one would expect. Rather, when glycogen is low (as a result of low carbohydrate consumption), the amount of protein and amino acids consumed does not appear to reduce muscle degradation for gluconeogenic amino acids. In other words, consuming a high protein and low carbohydrate diet leads to an eternal state of slow muscle degradation, the same as working out for weeks on end. While it is possible that the muscles will be ultimately be resupplied with amino acids and suffer no net loss, it is healthiest for weight loss and strength gain to supply the body with adequate carbohydrate fuel, and to use amino acids as a backup buffer, not the primary fuel.