Yes this frequently happens to me too. If thin, i increase food intake and before I will gain an inch of belly fat, my muscles will grow noticeably. If you want a non-anecdotal example, I recall watching a UK tv documentary about weight/weight loss and one of the guys put on weight (not body fat) and they realised that an increase in calories had actually made the guy grow muscle.Yeah... I'm not sure about that. You're saying you built that much muscle by not doing anything but eating?