Control eating junk

I know what how to diet
And what to eat
But I cant control my self when im around people who are eating fatty foods..then I start
What can I do to control myself?

ok this is what I did, sounds bad but helped stop the cravings, I didnt eat breakfest and just had a little snack for lunch, but then I would chow down on diner and it just made me not to crave anything and drink a lot of water, it just seems to keep me not thinking of food

try to drink a lot of water if you know your about to be going somewhere that you will be tempted because believe it or not it actually fills you up alottt