Imagine that you are training a male client who has a medium sized build, is more muscular, and has a considerably amount of lean mass. What would portion control look like for this individual

First of all, I would take Body Mass Index of the male client to have clear idea about the amount of weight he is above or below the healthy weight bracket. Then I would take the fat test to have a knowledge about the excess of less fat in his body.

If he would be below the desirable fat level in his body, I would recommend him with a portion in which he would likely to take more good fats in order to develop healthy fats in his body. Similarly, if his fats are above the healthy range, i would restrict him to take bad fats like oils, creams, etc in his diet.

Now as in this question, the client has a muscular lean body, which means he is in the pretty healthy body type, so i would suggest him to eat everything including carbs, good fats, proteins, etc, but in small quantities.