Had a friend in university, he did military service for 1 year and the only thing he had for breakfast during that time was a strong black coffee without any sugar nor milk.
He screwed up his digestive tract for good - there is apparently something in coffee that is quite aggressive on stomach and gets neutralized when mixed with any sugar/milk/food. He will never be able to eat vast array of common foods - things like marmelades and other basic food. Sorry I don't have any further info, has been few years ago.
He might have some unique predisposition for this, don't know, but better be careful and put at least some milk in it. It makes it much more filling anyway
He screwed up his digestive tract for good - there is apparently something in coffee that is quite aggressive on stomach and gets neutralized when mixed with any sugar/milk/food. He will never be able to eat vast array of common foods - things like marmelades and other basic food. Sorry I don't have any further info, has been few years ago.
He might have some unique predisposition for this, don't know, but better be careful and put at least some milk in it. It makes it much more filling anyway