I'm not a teacher but a student and I want to add my two cents to this discussion.
I personally always ate in my college classes that were on dinner or supper time. I didn't think it would bother anybody and it would save me a lot of time.
Until I had a classmate who did the exact same thing and it was so frustrating.
First, eating makes noise and it disturbs not only the person that eats but the others as well. Also, the smell can do the exact same thing.
And you can't really concentrate on a course while eating, I find the less I do things, the more I understand.
If I was a techer I would not allow food, it's not the same for drink.