Yes, coffee is great, for the body and the mind, but not on an empty stomach, it shouldn`t be the first thing you consume after you wake up. This increases the production of hydrochloric acid in the digestive tract, which is bad for the food that gets in the stomach.
This acid is one of the symptoms of gastritis. Also, it causes problems when you eat some heavy food, causing difficulties in digesting proteins. When proteins get absorbed while not fully decomposed, they cause problems like bloating, irritation, vomiting, bowel inflammation, even colon cancer.
Drinking coffee in the morning, on an empty stomach is also not recommended because it increases the levels of cortisol, so it will take a while for the body to restore balance.
So, always have your breakfast before your morning coffee. If you don`t have time, or you just can`t eat anything before the coffee, at least put some milk or butter in it to reduce the harmful effects it has on your body.