I'm on my second bulking diet (ever) and I noticed something weird. The first time I bulked, I got up as high as about 180lbs. The amount of calories that I was eating then at 180lbs was about 500 more calories than I am eating right now. The thing is, right now I am about 160lbs. How is that possible? How could just a 500 calorie difference make a 20 pound difference? What am I not understanding here?

Thanks in advance.