Hi Julie, welcome to 3FC!
With your example of 2 cups milk and a banana, I wouldn't exactly consider it unhealthy. If you do 2 cups of skim (180 calories) plus a medium banana (another 80) then you're at 260 calories which isn't bad and would probably be a nice snack or start to a good breakfast. Of course, if you're talking 2 cups whole milk then that's almost 300 calories from milk alone!
For me, calorie counting is about trade offs and flexibility

If you need any ideas for snack, meals, and more there are tons of great suggestions all around the forum and everyone's always willing to help out. Hope you like it here