I would say that it depends on your metabolism. I have to drink skim no matter what simply because I have a slower type metabolism. Lower in calories and real low in fat. A lot of my friends though can bulk up drinking a gallon or so of 1-2% per day and make some great gains without getting fat. 1% contains around 100 calories for every 8 ounces and 2% is 120 calories while whole milk is 140 calories. If your the smaller skinnier type, I dont think the extra calories from fat will affect you too much. Hopefully Mr. X will respond.