I am currently taking N-Large II since I have a very high metabolism and must consume about 3,000 calories a day to maintain my body weight. I weighed in at 140lbs before taking it and now a week later I am up to around 142-143. I want to slow my gains to about a pound a week and N-Large allows me to hit my caloric need of around 3,500-3,700 calories. Great product, buy it. Check out Mighty One by Optimum Nutrition. It has more calories and a cheaper price: I'm buying this next time since I need the cals.