I also ask a blessing on the food. Those who don't pay attention to their prayers tend to always ask that it will nourish us. But I try to be realistic. My personal kryptonite--oreo milkshakes--are about as bad for me as they could get. Sure there is a bit of dairy and protein. But they're drowned by sugar. I try to be honest in my prayers and not ask for silly miracles when I know what I'm putting in my body. So instead of asking for it to give me nourishment, I ask that I will enjoy it.
I do almost always ask that I won't get sick from my food. This probably stems from a couple of bouts of food poisoning. One of them was from food in a metal can and was quite severe. That was some of the most intense pain I have ever been in. I don't think it is beneath me nor my Father to ask that food not make me sick. Of course, I've also learned that I need to do my part in being wise in food choices and preparations.
Food prayers may include other things. Depending on what is going on for/with me at that point of the day, I sometimes give a report of what's happening. Or give thanks for things that haven't so far in the day. Or ask for help in something still to come. The prayers become little checkpoints in the day and give me yet another reason to talk with my Father. However, I do try to keep in mind what my father once taught me after I said a food prayer for family dinner: "Remember that when you're saying a blessing on the food, just say a blessing on the food." I guess I tended to be a bit verbose even when I was younger. But I liked that his point was to be to the point for a blessing that is meant to be more specific.