Will eating too much protein make you fat?

According to Maximum Fitness magazine, the most likely way protein will make you gain weight is if you're getting your protein from sources that also contain high amounts of fast-digesting carbs and unhealthy fats. Other than that, it's unlikely (not impossible; just unlikely).

For protein to be converted into fat, it has to first be converted into glucose -- this process requires the body's glucagon level to be higher than its insulin production. Nevertheless, this typically occurs only when food has not been eaten for at least four hours. So, again, the risk of protein leading to weight gain is minimal.

Apart from weight gain, it was previously believed that consuming high amounts of protein could negatively effect kidney function. However, research published in the Journal of Nutrition and Metabolism put this fear to rest. As a general rule, an active person should aim to consume around 0.8g per kilogram of body weight.