Q: I have read that in order to lose the last bit fat of belly(when u are already thin)is to bulk up then restart diet again.Only this way will go and not with cardio.This way use models and bodybuilders also.Is that correct?And if so how much bulk up u need to do in order to achieve that?

A: That is exactly correct and it is the best way to tackle the last bits of fat if you're already pretty thin. There's no hard rule saying you need to bulk up so much. The goal is to bulk up putting on as much muscle and as little fat as possible -- this requires very slow weight gain, a good diet, and of course a good training program. After at least couple of months of a good bulk like that, you can start cutting back down again, but you could also keep bulking longer, especially if you're noticing quality muscle gains without much new fat. Judgements like that ('quality muscle gain', 'not much new fat') are subjective of course, but that's the whole point: only you can decide how you want to sculpt your body. Check out http://www.mikesfitness.com/content/10-percent-body-fat-still-have-belly... and http://www.mikesfitness.com/content/8-percent-body-fat-want-abs for somebody else's experiences and my recommendations for tackling that same problem. Good luck!