The idea is to have a pattern allowing yourself to eat when you're hungry, stopping when you're satisfied. In general, I recommend eating meals, but not grazing. I get hungry between work and class, and sometimes it's just easier to grab a soda or candy bar. I don't like to carry a cooler around, either. A couple of satisfying foods that you can carry with you are string cheese, fruit, hard-boiled eggs, a carton of yogurt or breakfast bars or cereal bars.
Beverages do contain a lot of calories.
Some of the iced-coffee beverages have as many calories as milkshakes. And smoothies can often have as many as 500 calories per serving. So it is important to watch the number of calories you're drinking as well as eating. Yes, there are some kids that do lose weight when they first go off to college. But the pattern is that most kids tend to gain weight.