A Wrinkle In Time
Why does the food that the man with the red eyes gives the children taste horrible to Charles Wallace?

His mind is too strong, so the man with the red eyes cannot trick his brain into thinking it tastes good.

Charles Wallace is allergic to all of the food that the man serves the children.

Charles Wallace has been tricked by the man with the red eyes to think the food tastes bad.

Charles Wallace knows the food is fake, while Meg and Calvin both believe that it is what it appears to be.