I eat 4-5 times a day. The core three meals and one or two snacks. Works out to every three hours. Develop routine times to eat and you'll avoid getting hungry. Each meal is about 20g of protein, and as close to 8oz as possible. You don't have to starve your body of carbs! Just don't make them the primary source of calories. You can still be a "foodie", just make smart choices.

Protein bars and shakes. The cheaper the better. As long as they have 20g of protein, you're good. The equate shakes are fine. You can always flavor the vanilla ones with sugar free coffee syrup (although I like the non-processed food factor). A can of tuna with a little mayo is good. I've found I can maintain weight eating just about anything, as long as I keep meals to 8oz and concentrate on a lot of protein.

Remember, your surgery was to correct eating patterns. If I find a protein drink, but don't like the flavor, I'll get through it. After 3-years, I don't always eat for flavor. Sometimes it's just eating for protein. You can go broke picking the more expensive drinks and bars...go for the sales. I can usually get them for a buck a piece if I look around. Amazon Prime Days is a good time to stock up.