When people are trying hard to gain muscle mass they end up feeling frustrated and most of the time they wind up gaining a lot of weight as well. So many people would ask how to gain muscle without ending up being fat? Nobody wants to be fat. In reality, I'd say that 9 using 10 people get into building muscle to get a more toned and muscular body rather than a fatter one. These days to weeks, a lot of people are trying to build a lean more athletic looking body, rather then simply a bigger more sexy body.