with that being said...here are the benefits of over eating protein.
Increased Thermic Effect of Feeding — While all macronutrients require metabolic processing for digestion, absorption, and storage or oxidation, the thermic effect of protein is roughly double that of carbohydrates and fat. Therefore, eating protein is actually thermogenic and can lead to a higher metabolic rate. This means greater fat loss when dieting and less fat gain during overfeeding.
Increased Glucagon — Protein consumption increases plasma concentrations of the hormone glucagon. Glucagon is responsible for antagonizing the effects of insulin in adipose tissue, leading to greater fat mobilization. In addition, glucagon also decreases the amounts and activities of the enzymes responsible for making and storing fat in adipose and liver cells. Again, this leads to greater fat loss during dieting and less fat gain during overfeeding.
Increased IGF-1 — Protein and amino-acid supplementation has been shown to increase the IGF-1 response to both exercise and feeding. Since IGF-1 is an anabolic hormone that's related to muscle growth, another advantage associated with consuming more protein is more muscle growth when overfeeding and/or muscle sparing when dieting.
Reduction in Cardiovascular Risk — Several studies have shown that increasing the percentage of protein in the diet (from 11% to 23%) while decreasing the percentage of carbohydrate (from 63% to 48%) lowers LDL cholesterol and triglyceride concentrations with concomitant increases in HDL cholesterol concentrations.
Improved Weight-Loss Profile — Brand spankin' new research by Layman and colleagues has demonstrated that reducing the carbohydrate ratio from 3.5 - 1 to 1.4 - 1 increases body fat loss, spares muscle mass, reduces triglyceride concentrations, improves satiety, and improves blood glucose management (Layman et al 2003 — If you're at all interested in protein intake, you've gotta go read the January and February issues of the Journal of Nutrition. Layman has three interesting articles in the two journals).
Increased Protein Turnover — As I've discussed before in my article Precision Nutrition, all tissues of the body, including muscle, go through a regular program of turnover. Since the balance between protein breakdown and protein synthesis governs muscle protein turnover, you need to increase your protein turnover rates in order to best improve your muscle quality. A high protein diet does just this. By increasing both protein synthesis and protein breakdown, a high protein diet helps you get rid of the old muscle more quickly and build up new, more functional muscle to take its place.
Increased Nitrogen Status — Earlier I indicated that a positive nitrogen status means that more protein is entering the body than is leaving the body. High protein diets cause a strong positive protein status and when this increased protein availability is coupled with an exercise program that increases the body's anabolic efficiency, the growth process may be accelerated.
Increased Provision of Auxiliary Nutrients — Although the benefits mentioned above have related specifically to protein and amino acids, it's important to recognize that we don't just eat protein and amino acids — we eat food. Therefore, high protein diets often provide auxiliary nutrients that could enhance performance and/or muscle growth. These nutrients include creatine, branched chain amino acids, conjugated linoleic acids, and/or additional nutrients that are important but remain to be discovered. This illustrates the need to get most of your protein from food, rather than supplements alone.