Just thinking here, cottage cheese and any kind of frozen fruit would be good. I make my smoothie a little different. ( Not diet food) I put a banana, heaping spoonful of peanut butter, spoonful of sugar, a cup of milk and a cup or so of ice into a blender and blend until the ice all chopped smooth. It comes out like a milk shake. Grandkids love it too, and sometimes for them I add some choc. syrup.