It is best to sing on an as close to an empty stomach as you can tolerate. You don't want to be so hungry that your stomach is growling, however you don't want excess food in the stomach either. Any contents in the stomach will restrict the diaphragm and can cause you to sing out of key.
Should you eat before you sing?
GOOD: Honey – one of the best foods to eat before singing is honey as it soothes the throat (now you know why so many lozenges have honey in them!). Mix honey with warm water and a little bit of lemon juice (not so much as lemon can dry the throat) to get a particularly soothing and calming drink before you sing.
Does eating affect your singing?
Stomach acid may fall onto the vocal folds, irritating or burning them, causing discomfort and temporary vocal damage that can be further aggravated by singing. To prevent these negative effects on the voice, it's best to steer clear of meals that may trigger reflux and heartburn in the days before a vocal performance.
Should I sing on a full stomach?
Singing on an empty stomach is not recommended because doing so can affect your energy levels, especially if you're planning to sing for an extended period of time. ... Singing on an empty stomach can also cause your stomach to growl and rumble, which can be especially uncomfortable on stage.