If it you it to the extreme, sure. But the foundation of losing weight in any context is calories in < calories burned.
I tried to get my dad to stop drinking soda for years when I was growing up. Dude drank 8+ cans a day. He finally quit drinking soda, and was for some reason surprised when he started losing weight. Changes as simple as that, just ordering a size down of what you normally would when you do esst fast food, etc. all can add up big time.