Soup only postpones the reckoning, but it DOES help. Why? Because it takes away the worst of the symptoms by returning the body to a condition of anaethetization. That dry mouth, that nasty headache--they're largely the result of water loss--and soup restores the fluids.
Carbohydrates also help. They help correct the derangement of acid balance in the tissues that causes feelings of fatigue and malaise.
Bottom line--what every mother knows--when you don't feel good, eat soup. Chicken or otherwise.