I like the stuff. There's some kind of special lipid they use in it which promotes more fat burning and muscle energy than fat storing, so it's really a fat-burner so I wouldn't worry about gaining weight while on it (I never have). About the calories, I'll quote what it says on the back: "While Muscle Milk may contain slightly more fat than low fat and high carb products, our LeanLipids are designed to help you get leaner." I usually take it after I lift rather than after boxing and it does make a noticeable difference but Im sure it will help after boxing as well(I take half the dosage and it still does the job, and really does make you leaner). I think it also aids in muscle repair and supposedly promotes natural creatine production. -If you do get it, I'd suggest getting strawberry flavor, everything else is disgusting in my opinion. Let me know if you want to know anything else specific about it and maybe I can be more helpful than this.