With this cutting diet plan we can guarantee that you will lose weight and become more lean through four weeks of healthy eating. Its worth noting, however, that as this diet plan is designed to help you shed fat and lose weight, gaining muscle mass will be difficult. would this diet loss muscle or help gain muscle. The Ultimate Muscle Building Diet Plan for Men with Diabetes Calories, calorie goal for fat loss, mass gain or body weight maintenance. Tags Fat Loss Training Diet Strategy. If you gain fat easily, following the diet and training advice meant to help skinny bastards gain. Instead, opt to replace carbs with healthy fats and keep your protein intake constant.