Rule 1 Gain is a high calorie lean mass gainer that contains high quality nutrients. It includes 530 calories per serve which is ideal for guys who are looking to build muscle size and pack on weight. It is primarily made up of whey protein isolate which makes it quite fast digesting and also low in fat. Rule 1 sees the importance of what goes into their products especially when it comes to mass gainers. Exclusive to Rule 1, it has a ratio of 1.5 to 1 carbs to protein which offers a quality approach to gaining lean mass without loading you up with too much carbs.