Tomatoes have high speed and good range, but you have to aim them precisely.
Bananas are more forgiving of aim errors, but tend to curve as they travel.
Peas are easy to aim because of their spread, but have limited range.
Pies are sort of good at everything, but great at nothing.
Watermelon is a lot like pie, except you trade infinite ammo for slower projectile speed.
At higher levels, basically the food variety becomes irrelevant. At those speeds, the chefs have to be directly in your path of travel or you'll never hit them.
One time I was having spaghetti and I yelled Look! It's the Flying Spaghetti Monster and I threw it at my hubby so yeah, spaghetti works great. It came out of my white shirt eventually.
General Tso's Chicken would also be a good food for a food fight because being General Tso and all, he really wants to fight.