Yes you can build muscle an lose fat, muscle growth is also to do with a positive nitrogen/protein balance as well as an abundance of calories. Plus as you start the body will use almost all the extra calories to build tghe muscle as this will be more important to it than holding on to fat.
In addition to this, the more muscle you have the higher your metabolism whilst resting which means that fat will also be burnt, also as the muscle grows even if the fat remains constant then bf% (which is what makes you look fat or not) will also reduce, giving the appearance of losing fat whilst gaining muscle.
Its not easy obvuiously, but if you are young and just starting then there is no reason why this shouldnt happen naturally, for a while at least, as long as, like people have said, DIET is in check.
TEAM CROM (supporter) !!!!