Yes, too much protein is harmful to your body. The recommendation of protein intake is 1g per kg of your weight. For instance, if you weigh 50 kg, you are then advised to take 50 g per day. Furthermore, if you go to the gym or you are an athlete or sportsman, you may need a protein intake of up to 2.5 g per kg of body weight. Additionally, if you take too much protein without doing any workout, you will gain weight.