Fermented foods are those food which has the probiotic bacteria in it, these bacteria are good for the digestion and also protects the layer of the intestine, these foods are good for the proper digestion of the sugar content of the food and also gives us good amount of energy throughout the day, you should add these foods to you daily diet, so that your stomach will be healthy, here are list of some of the fermented foods.
Tempeh is the one of the best sources of the probiotic bacteria and it is obtained from soy. It has many health benefits such as ,it helps in maintaining the blood pressure, reducing the chance of heart attack, very beneficial for people who are suffering from digestion problems because it is easy to digest as it contain enzyme and probiotic for boosting up your metabolism rate of the stomach. Tempeh are rich in protein, iron, calcium, fiber. 
kimchi is delicious fermented Korean food that are loaded with probiotics, high in fiber that prevent constipation and stabilize the movement of bowel, powerful antioxidants that maintain the oxidative damage and protect the body from oxygen free radicals. It has many health benefits, as it lowering the chance of cancer because glucosinolates present in kimchi made with cabbage, fights against cancer cells, reducing the high cholesterol level, control diabetes, provide healthy digestion, fight against viral infection disease like cold and flu. Kimchi contains lactobacillus bacteria that provides relief from irritable bowel problem and heal your gut. 
Yogurt is excellent milk product which is found to be very healthy for your body, even milk is first converted in the curd and then our body digest it, yogurt helps in protecting you from various disease. Yogurt is good food for your digestive system, as it eliminates harmful bacteria from your digestive system and helps you to be protective from intestinal infections. It contains high amount of potassium, that helps in flushing out excess sodium from the body, it also helps in reducing the high blood pressure, protecting you from osteoporosis due to presence of micro nutrients in it. 
Kombucha is a delicious drink made by fermenting of the black tea, yeast, sugar and water. It is a probiotic drink as it has many healthy bacteria, enzymes and yeast that is very good for your stomach and easy in digestion of the hard substances of food. It contains powerful antioxidants such as DSL, vinegar, lactic acid and vitamin C that helps in cleaning and detoxifying your body, lowering the joints pain and boost your immune system. 
Sauerkraut is an amazing fermented food, which is used to solve the digestive problems and has an ability to boost your immune system. It is an excellent probiotic food made with fermented cabbage, it contains powerful enzyme, lactobacteria, vitamin C, high fiber that are beneficial for maintain healthy brain, reduce the extra fat from body and reduce cholesterol level. The presence of probiotics in sauerkraut helps your body to absorb the vitamins and minerals from the food easily by increasing intestinal flora and balance of bacteria in your stomach. 
Natto is known to be the best source of the dietary fibers, which ease the metabolism rate of the stomach, you will get it by the fermentation of the soy beans, it has the vitamin K2 in it, which removes the calcium from the arteries and helps the bones to consume it, so that you will have healthy bones and heart.