I tried this, with sliced banana. And my granddaughter, with the absolute honesty of a 4 year old, told me it was “a little bit disgusting”. LOL. Basically what happens is the banana gets kind of slimy as it sits in the liquid overnight. So if you are picky about textures (which is everyone in my family) then I recommend you add the fruit at the time you are going to eat the oats. If using jam, you can add it as you are making the oats. Just layer it on top of the oats before covering with the lid. Then mix it in the following morning.