Personally, and I know not all will agree, but as long as you stay at 800-1000 a day, you will lose. So you can eat/drink anything that your band will tolerate. Dense food (steak etc) and carbs (noodles, rice, bread) are very hard for me to eat. Try to get 60-80 grams of Protein a day, 60-80 ounces of Water and 1000 calories or less and 3 hours of exercise a week and it will really start to come off (300 calories or less per meal is my goal, usually less in the AM when I am tighter).
In the morning I try to get my protein in so I drink a chocolate premier Protein shake (buy at costco, only one I can tolerate) with coffee (160 calories, 30g of protein). Then for lunch, I will have a bown of Soup, lunch meat, chicken (200-300 calories -- in the begining I ONLY ate stuff I could tell how many calories I was getting, look at labels or menus with calories counts), then for dinner a piece of meat and some veggies (300 calories plus 30+ grams of protein). For Snacks look for protein bars/shakes (or maybe a few nuts but be careful not to eat too many).. but try not to snack at all if you can help it. Drink your water all day to keep you feeling full.
good luck. I hope this helps.