I would be very careful in Mexican restaurants. Refried beans are almost inevitably cooked in lard, as are many other beans. The rice is oily.
I agree that sometimes you just need to say, "I won't DIE before I can get home to get food," b/c let's face it--it's true! Hunger isn't there to say, "OMG! Hurry up and eat or you'll be dead in 10 min!!" It's there to say, "Hey--the stomach could handle some food. No rush--whenever you have the time."
Adjusting your attitude about this is a big part of being successful.
Another part of being successful is planning ahead. When I know I'll be out for much of the day I take along a small cooler w/ cooked taters, fruit, carrots, and sometimes even some leftovers. It's rare that I'm caught with "nothing to eat" and when I am, I just remember that it would take me WEEKS to die of hunger.