Stomach respond differently to food when it is empty. Even some healthy foods is not healthy to eat on an empty stomach, because it can cause acid stomach problems, diarrhea and the like.
What is not recommended to eat on an empty stomach
Tomato. Consumption of tomato on an empty stomach can increase stomach acid because it contains tannic acid. This increases the risk of ulcers.
Coffee. If you drink coffee on an empty stomach, it can increase the acidity of the stomach and damage the stomach lining. Some people do not mind more and some less, so that each individual case. And again, if you drink coffee immediately after meals, it interferes with the passage of some minerals, e.g., calcium and iron. Therefore, it is advisable to drink coffee only about 2 hours after a meal.
Citrus fruits. Oranges, lemons and other sour fruits can cause problems in people who have problems with the stomach, heartburn or inflammation of the esophagus.
Fizzy drinks. Carbonated beverages, whether or not sweetened (mineral water) on an empty stomach can damage the mucous membrane of the stomach and lead to a reduced blood supply of the stomach.
Sweetened beverages (including freshly squeezed juice). When taken on an empty stomach very quickly raise blood sugar levels, and therefore increase the hunger and desire for food in general. It is better to use them after meals.
Hot spices (e.g., ginger, pepper, etc.). On an empty stomach, they can strongly stimulate gastric acid secretion and damage the stomach lining.
Yogurt. If you eat yogurt on an empty stomach, concentrated stomach acid will destroy the probiotic lactobacilli contained therein, so that one of them is certainly that you will not benefit.