为什么要吃早餐？（用英语答）

It is good for our health and keep fit.

Because it's good for your health.:)

You may become huangary if not.

为什么要吃早餐？Why do you take breakfast?

不是 eat breakfast. 这是常犯的错误， '早餐'(这个名词) 是不可以吃的。
take 是用的意思