Many people today have digestive problems due to low stomach acid, which has similar symptoms of having to much stomach acid: heartburn, sour stomach or an overall upset stomach. Stomachs produce hydrochloric acids to digest food in the right amount, so that it doesn't effect the lining of the stomach itself. But if too little stomach acid is produced, it can ulcerate the stomach lining, as it will also not be producing bicarbonate of soda, which protects the stomach lining. However, certain foods can be eaten to aid or reduce this.
Coconut oil, butter, lard and other naturally occurring animal fats are good to consume until your stomach acid production goes back up, as they are high in protein, which stimulates the production of stomach acid. They also stimulate the liver to produce bile which is necessary in regulating stomach acid levels. However, it's important not to get into too much of a habit of this, as even "good" fats can affect your overall health.
Sauerkraut or Kimchee
These two pickled vegetable dishes contain a lot of helpful things to stimulate acid production in the stomach. These can cause healing reactions to "candida"--the term for the disease that causes someone to have low stomach acid in the first place. Eating unheated sides of these are important, especially since cooking these will make the molecules within them bind together more and make them harder to digest.
Ocean Sea Salt
It's a good idea to start eating ocean sea salt--some of the purest salt--with every meal. Salt is important to overall digestion, but it also stimulates the production of acid in the stomach. Again, this is another food you only want to consume until your stomach acid is back to the level it should be. If the problem persists, consult a doctor and consider taking betain hydrochloric acid supplements to supplement your digestion after eating.