This seems like something many young adults work out in college. The "freshman 15" is exactly what you're describing except with the school dining hall instead

This seems like something many young adults work out in college. The "freshman 15" is exactly what you're describing except with the school dining hall instead of the workplace cafeteria. You just need to learn to say no, it's really as simple as that. If that's not possible consider you may need medication like Vyvanse or other medical help to stop your excessive eating.