I don't, personally. I figure a few days of light eating, if I don't feel like eating, will probably not cause too much damage, in the overall scheme of things.
The less I eat, the more nutritious I try to eat, though. I'll make a smoothie or something, to get in fruit and milk, or maybe cook one of those single-serving veggies. Or some peanut butter on an apple. Or black bean soup. Not just, say, ice cream (which I have also done before, when sick, admittedly).
I was feeling this way a couple of weeks ago. Just not well at all, and no appetite. I didn't make myself eat a full day's worth of food, though. I did find a new favorite comfort food: brown rice and tofu. Bland yet tasty, and kind of comforting.
I do also try to eat more if I truly feel hungry, if I can tell it's not just thirst. The deal is, I eat healthy food, just more of it, if I'm really hungry. I figure, it'll balance out eventually.
Then some days I just pig out still.