The science says x amount of protein to y amount of carbs (3 to 1 up to 4 to 1) but I don’t always follow it and adjust according to my workout. For example if I’ve done 60 mins climbing hills I’ll take in more protein at maybe 1:1.
Personally as a general rule, and considering the above, I’d add some protein (yoghurt, milk or protein powder or all) but berries are high in anti oxidants, bananas have potassium so you are replacing some essential nutrients and helping recovery as far as I know, I don’t see a downside to eating whole foods. Cereal wise I add oats.
Oh and blueberries are just so tasty too, watch the sugar intake though