You can let your snake's body condition be your guide; it's better for him to be on the skinny side and then you increase his food rather than letting him get chunky and trying to get him to lose weight.

I feed my adult male about once a month, and he does well with that. A lot of the advice about feeding you'll find is really geared toward either juveniles or breeders, which may fast while breeding or expend a lot of calories in the process (females producing eggs).

There are a lot of overweight pet snakes out there. Overfeeding shortens their lifespans. Also, I suspect that a lot of the famous ball python fasts are related to feeding frequency - basically, the snakes regulating their food intake. Eating every couple of weeks and then fasting for six months works out to the same number of meals as eating once a month all year.