This always seems to confuse people... theres a protein minimum and a fat minimum, the rest of your calories come from any mix of macros. You choose to have that be almost entirely carbs, so when you...
because adequate levels of fats are required for body function and health... nobody is recommending you swap all your carbs for fats, just enough of them...
maybe that's what he's doing... id rather he didn't, it wouldn't take long to explain that some people eat more calories then others w/o bringing Santa Klaus into it...
The same thing that would happen if he bulked then cut to 170 at say 15% but many many times slower and with much less future potential gains assuming this is always done.