Someone once told me "You can't out-train a bad nutrition plan",
with that said...in order to maximize muscle gain and fat loss, you need a GOOD nutrition plan.
If it's a well balanced plan then you COULD get away with it. Yes you will lose fat but only for a short period of time.
Consider this...Your muscle is ,so to say, the engine that burns most of your calories and plays a substantial role in metabolic rate.
If you ONLY focus on the nutrition plan, with NO exercise, you're not increasing your resting metabolic rate meaning that in the long run with more muscle you will burn more calories (just by sitting there)
Not only that, but your muscles will use up many calories when exercising to recover.
Summary:No exercise=results will come slow and plateauing fat loss
Exercise=results will come much sooner and will burn more calories in the long run
Good Nutrition+Exercise+Consistency= SuccessI wish you all the best, hopefully I was of help to you

Cheers,
Dmitro
No matter HOW slow you're moving, you'll ALWAYS be lapping the ones on the couch...