Excess calories turn to fat although protein because of the way it's metabolized is less likely than fats or carbs.
The majority of protein digestion takes place in the intestine which can handle b/t 300-400 grams so it's unlikely that you will eat to much protein in any one meal. Whenever you read that the body can only handly 30-50 grams at a time, the article was written by someone who hasn't a clue and is following the myth.
So that you don't feel discomfort you may not want to exceed 100 grams or so per meal.