Mass Gaining Diet - Ep53 (Mass gaining diet plan for skinny guys) Gaining mass needs a solid muscle gaining training program but a successful mass gaining diet should form the basis of your muscle building plans. Resistance exercises begin muscle growth but its your nutrition that ends it and builds your body. in Public bookmarkswith mass_gaining_dietmass_gaining_diet_planmass_gaining_plan Note: Gaining mass needs a solid muscle gaining training program but a successful mass gaining diet should form the basis of your muscle building plans. Resistance exercises begin muscle growth but its your nutrition that ends it and builds your body.