Well, that's a little tricky because everyone is so different. I'll start with food allergies. Apples, carrots, nuts, and peaches are frequent offenders. The allergic reaction can create swelling so that you sound like you have a cold. Carbonated beverages are another hidden trouble spot in some people. The bubbles make for more reflux and belching and irritate the vocal folds. Milk /dairy are often mentioned, but these are more trouble for people without lactase to digest dairy or people with allergies to milk proteins. Usually, it's the allergic response that makes the mucus worse and not a direct result of drinking milk itself, though in some people that can happen.
Lastly, it's often about the timing and the size of the meal. Eating a large meal full of simple carbs will leave you feeling bloated and in a few hours, you'll be tired. So that meal is not a good idea before you go into the studio or on the air.
Anyone else have something to add?