When to Eat
Think of yourself as an athlete and eat that way: an athlete wouldn't stuff herself with food just before running the mile and neither should you. A full stomach inhibits the movement of the diaphragm-you'll have difficulty taking in full breaths and you'll be prone to burping. Don't starve yourself, either--singing is hard work, you need fuel. A normal meal an hour or two (two is better) before a singing session works best. If you need to eat between sets go for non-bulky, easy to digest food. Before a show I like eggs--high protein, low density. .
What Not To Eat Or Drink Before Singing
Foods that add mucous: milk, ice cream and other dairy products
Foods that dry the throat: citrus fruits, alcohol
Throat Irritants: Overly spicy foods, coffee
Sodas and other fizzy drinks put lots of air in your stomach
Ice cold anything: your throat will constrict. Warm water or herbal tea is best
What's Soothing To The Throat
Liquorice tea or candy (experiment with this, some people get an uncomfortably speedy buzz from liquorice), baking soda or salt water gargles (see below), honey, sugar lozenges, steam, certain herbal teas -- which teas to drink varies from person to person so experiment.
What Helps To De-Gunk The Throat
You've probably heard that honey/lemon/and hot water are helpful if you have mucous in your throat. But remember that lemon is drying so don't overdo it. I prefer gargling, here's the best way: If your throat feels gunky and/or irritated: mix 1/4 teaspoon baking soda + one cup warm water. Take a small amount of fluid in your mouth and gargle at a high pitch-this causes your vocal cords to contract and rise closer to where you are actually gargling (your epiglottis will prevent the fluid from actually reaching your vocal cords). Spit and repeat several times.
Pollen season or other allergies hit, you get rear-nasal drip, and it drips down to your vocal cords and irritates them. Prescription allergy medicines can overly dry out your cords. Instead, clean out your nose with saline then line it with vaseline or its equivalent. This prevents the allergens from getting into your system and setting you off. This won't help after an allergic reaction, but do it first thing in the morning as a preventative measure during allergy season.