Re: the metabolism specifically, for most my life I was chubby and just assumed that I had a slow metabolism. Then I went to college and saw that I was eating maybe three times as many calories anyone else. Oh, and more recently, the other day, my roommate, who has been trying to lose weight on a reduced-carb diet, confronted me with, “So, I saw from the garbage that you cleaned out an entire quart of ice cream last night, yet you’re still dropping weight? You bitch. You sonuva bitch.” So I’m probably slightly advantaged in how much slop I can get away with in my diet. Though I doubt this consolation prize makes up for my fragility and crappy explosiveness.
That said, I think it’s less diet/BMR and more just the volume and pacing of training. Last year, when I was training on my own and doing basically a powerlifting template, I was resting a lot between sets and doing only 1-3 exercises per session. Now it’s more like 3-5 exercises, for maybe 2x as many reps each, and a snatch or snatch variant is for me much more taxing than, say, 5x5 press. Also, I am down to 1:30-2:00 rest between sets, and my anaerobic capacity has improvedly markedly. I know it’s tempting to take a lot of rest when chasing big singles and doubles, but maybe for lower weights, keep those rest periods down.
And of course, the dreaded Prowler comes into play much more now than before. That thing is a religious experience sometimes.