you only need to overeat if you are training rediculously hard in order to keep up with metabolism
you lose fat by not eating much VERY SIMPLE CONCEPT
if you want to gain muscle quick as you possibly can than you need to make exercise the most important and most time consuming activity everyday and eat alot to have energy and repair for next day of rediculous training in the gym....this personally is the most enjoyable , because like adonis ill eat pints of icecream and waffles with butter everywhere and not really get fat because my training is really intense and very long 2-3 hours long when really eating alot. normally if im cutting ill just train 1.5 hours because i dont have enough cals in me