According to experts from Columbia University, research has shown that you should consume an additional 2,270 to 3,630 calories per week to build as much as a single pound of muscle during that time span. This equals about 500 additional calories per day. A typical 180-lb. male needing about 2,700 calories per day would therefore require at least 3,200 calories. Furthermore, an hour of intense weightlifting burns 500 calories. Added up, this same person may consume as much as 3,700 calories on lifting days just to properly bulk up.