Formula M.A.S.S. Weight Gainer is a unique blend that provides highly digestible fats, proteins, and carbohydrates to sustain energy for the athletic canine. The high energy density of Formula M.A.S.S. Weight Gainer is derived from premium quality vegetable fats that are of high nutritional value. Formula M.A.S.S. Weight Gainer also contains direct fed microbials to support gut health. Canines love the great taste of Formula M.A.S.S. Weight Gainer