Q: MUST one gain weight to gain muscle? Is it possible to gain muscle if one maintains a regular diet? This will result to slow fat loss during the duration of this plan, right? (as oppose to rapid fat loss after building up muscle, as you propose) By the way, at what point (how much muscle gain/time) do you think is adequate to then focus on fat loss? At this time, you just propose that we cut calories out of our diet to lose the fat, right? Thank you for clearing up these concerns in advance.

A: If you are new to weight training, you will be able to gain muscle without following a 'bulking' diet (i.e. overeating to gain weight) or even while losing weight. However your gains will be slower than if you had followed a 'bulking' diet. After your first year or so of weight training or once you've hit certain body composition (typically 12-15% body fat) such muscle gain will stop or become so slow as to be almost imperceptible. At that point if you want to continue to gain muscle, you will pretty much have to go on a 'bulking' diet.

There is no hard fast rule about when to stop building muscle and to start cutting fat. It's really up to you and your personal goals. My two general recommendations is to not try to 'bulk up' past 18% body fat and also not to 'bulk up' past the point where you have more fat than any time in the past. So a typical progression may be to start at 20% body fat, cut down to 14% BF, bulk up to 18%, cut down to 12%, bulk up to 15%, cut down to 10%... Any one phase may take half a year or longer because I recommend slow weight loss and even slower weight gain in order to maximize the muscle and minimize the fat.

You are correct that the change from bulking to cutting is mainly about the calories, but it should also incorporate changing carb-dense foods of the bulking cycle (hopefully whole grains, but likely to also include bread, pasta, rice, potatoes) to mostly leafy vegetables in the cutting cycle. The only meals during the cutting cycle when you'll want to have significant amount of carbs (again, preferably whole grains like oatmeal) is breakfast and the meals before and after your weightlifting sessions. At other times while cutting, your meals should be mainly veggies + protein + fat. Obviously nobody follows this exactly, but this is the goal.