For those of you who have a better grip on metabolism and diet, here's a question I have.
What would be the pros and cons of having a fast metabolism and eating a lot of food vs slow metabolism and eating less food (assuming that the net calories gained or lost is the same for both cases).

For example:
One guy is taking caffeine pills and his metabolism during a normal day (including workout) burns up 3500 Calories. But he also eats 3500 Calories a day. Guy #2 isn't taking any pills or anything and his natural metabolism burns about 2000 Calories a day. He also eats about 2000 Calories a day.

I guess what I'm trying to get at is whether or not one of the two examples would have an advantage over the other when it came to maintaining and gaining muscle. Perhaps the fast metabolism guy is more likely to have protein available for muscle synthesis, but on the other hand maybe his body is getting so much done that it could cause problems if his body didn't have protein readily available to build muscle.

Any ideas?