Beginners gain glycogen and water mass when they first start strength training programs. I’ve previously written about this here . This is a bit of an issue since “noob gains” are partially glycogen/water gains ( Ribero et al., 2014 ). This affects lean body mass (LBM), fat free mass (FFM), or cross-sectional area (CSA). Muscle glycogen/water content even affects MRI measurements ( Nygren et al., 2001 ). But, there are several studies that show beginners lose or maintain FFM when they go on a cut. Probably due to a reduction in carb (glycogen) or protein intake. Hence, it’s not a given that beginners will increase FFM when they train and cut.
Speaking of overtraining, lets talk about the other kind of rest, the time between workouts. How much rest you need between workouts depends a lot on your experience level. Beginners can workout every day or every other day where as an advanced bodybuilder would have to wait 3-6 days between workouts. Please note that when I say that an advanced bodybuilder needs 3-6 days between workouts, I mean for a particular bodypart. For example if you are advanced and workout chest on Monday then you shouldnt workout chest again till Thursday at the earliest. Its fine to do legs on Tuesday, back on Wednesday though!