Although it's best to get protein through regular diet, supplementing it with a combination of whey and casein is a good choice, as long as he can tolerate dairy well (no milk allergy or lactose intolerance), since both come from milk.
• Recreational athletes need 1- 1.5 grams of protein daily for every per kg of body weight
• Competitive athletes need 1.2-1.8 grams per kg
• Teenage athletes need 1.6-1.8 grams per kg
• Athletes building muscle mass need 1.4-1.8 grams per kg
The maximum amount of protein that most adults can use per day is 1.8 grams per kg of body weight. Body builders may go up to a safe maximum of 2.5 grams per kilogram body weight of proteins – some exceed this limit and consume up to 4.5-5 grams per kg body weight; which may very well be metabolically cumbersome on the liver and kidneys, predisposing to liver disease (non-alcoholic liver disease NALD) and kidney problems.
Taking protein powders immediately after a workout is a myth, because the main and most important fuel that the body needs before, during, and after a workout are carbs, they are what the muscles use to function, as research shows that with exercise, the body needs fuel with a 4-1 or 5-1 ratio of carbs to protein. Since most protein powders have at least 20 grams of protein per scoop, you’d need about 80 grams of carbs to go with that scoop to get the proper proportion of nutrients- Not advisable.
A better option for post-exercise recovery would be a fruit smoothie with yogurt or milk, or chocolate milk
The protein content of the different available shakes must be taken into consideration:
-A body builder needs drinks that have a bit more protein
-An endurance athlete, like a marathoner, requires drinks with more carbs.
-Individuals who exercise to lose body fat should go for protein shakes that contain mainly protein (50%), fewer carbohydrates, and only a little bit of fat.