The mass gainer that is best for weight gain right now is Naked Nutrition's Naked Mass (retailer link). It's not only super healthy, but each mega serving contains huge amounts of calories and carbs, making it at least a little bit easier to put on weight for people who can't stomach another portion of chicken and rice. Adding just one serving of Naked Mass can add as much as 1,250 calories to your diet per day. Now that's adding mass like a pro.