Ham and Steak are fine as are things like Chicken, Salads, Sandwhiches. Whole Wheat Bagels are not that bad, but you really need to set out some specific times to try and eat.
You could include things like Eggs in there, Low Fat cheese, Turkey, Nuts, Peanuts, Powdered Flax, Whole-grain Cereal, which at least will give you more options if you have any issues with obtaining or consuming Fruit and Vegetables.
You need to incorporate more meals in there. 3 is not enough. you'd be wise at least to have a couple of solid snacks, (calorie wise), not pissy low cal bars or something like that and they woud be between Breakfast and Lunch and Lunch and Dinner, then one again about 2-3 hours after Dinner, so you're at least getting around 2,200-2,500 calories a day.
You are a little hogtied though, because of the food your educational establishment chooses to serve and one of the households you go to sometimes.
Hopefully you've got a few more options now though