You can empathize with how your kid feels when he has a cold or the flu, because you've probably had a few yourself. If your kid's got a cold, he can probably still move around and play at home, but he'll be continuously sniffling, wiping his nose, and coughing. It may hurt or be hard for him to swallow, but it's important to keep him taking in fluids. A dry, raw throat will probably make eating unpleasant, so try to stick with liquid-based foods, like fruit smoothies and chicken soup.
If it's the flu plaguing your child, she probably won't feel up to being up and about, between the fever, fatigue and possible nausea. She might not feel up to eating or be able to keep anything down, but it's important to keep up fluid intake and offer small portions of bland foods.