High-Protein Weight Gainer Putting on size requires a balance of heavy training and quality nutrition. Because everyone’s a little different, some have a harder time packing on muscle than others. PRO Gainer is a high-protein formula delivering calories that count during recovery. Each shake provides ample amounts of supplemental protein, carbs, vitamins and minerals to build on the amount you’re getting through a balanced diet of food. Use PRO Gainer as your post-workout recovery shake and/or a high-protein meal between meals.