This is something you’ll often hear when researching the subject in “hardcore” bodybuilding circles. Simply eating more will not solve the underlying problem, however. Digestion is a very energy costly process. Your body has to work hard to break down and assimilate the foods you eat. Yes, you need to provide sufficient quality nutrition, but it’s much less than most people (want to) believe. If you’re eating every 2-3 hours, you’re never giving your body a chance to repair damaged tissue and eliminate waste materials.
If you try to train up to 6 hours total, 4 or 5 days per week, you will risk overtraining and make your body prone to injuries. That amount of exercise will make you feel mentally and physically drained, especially if you’re underweight. Understand the signals that your body is sending – if it’s sore, then it needs some time to recover. There is no building muscle without proper post-workout recovery, so don’t think that you will enhance your results by living in the gym. However, you’ll come back stronger once you provide your body the time it needs to recover.