A High Protein Diet Has No Harmful Effects
There is a popular belief that consuming too much protein can damage the kidney, liver, and alter blood lipid levels. A study by Antonio et al. in the Journal of Nutrition and Metabolism observed both a normal and high protein diet in a group of 14 resistance trained males and found no harmful effects to the extreme diet. The normal diet for the subjects included an average of 2.51 grams per kilogram body weight, and the high protein diet had an average of 3.32 g/kg bodyweight. To put this in perspective, the recommended daily amount of protein is 0.8 g/kg bodyweight. After the trial period, there were no altered blood lipid levels or damage to kidney or liver function. In addition, even with the excess calorie intake from the high protein diet, the subjects did not observe an increase in fat mass.
Consuming enough protein is imperative to helping the body recover from hard training sessions and to build muscle. For serious lifters, we suggest consuming at least 2.0 g of protein per kg of bodyweight. It is possible to consume all of your protein from meals if you eat a lot of high protein foods such as chicken, beef, milk, sweet potatoes, and nuts. However, it is much easier and more consistent to add a protein supplement to your diet. We recommend taking whey protein in the morning with breakfast and within an hour post-workout.
You can find the article here: https://www.hindawi.com/journals/jnme/2016/9104792/