Any idea why they say not to start your day with fruit?

Khushi I.
Because when we sleep at night, our body is in relaxation mode and our digestive system needs liquid. So, When we wake up in the morning, our digestive system starts to work again, for this we have to drink water in the form of liquid first of all when we wake up in the morning.

Christine U.
Who said that? I eat, not everyday, apples or bananas. As this app said that contain a lot of protein and vitamins.
But I get why some nutritionists say that fruits are not a great choice. They contain acid, if I'm not wrong, that for your morning stomach might not be the perfect start.