Calories from Keytones or Vice Versa

I have a question regarding ketosis and calories I was hoping someone could answer.  When we are not in ketosis and we consume calories our body converts the calories into sugars that are used as fuel for energy.  My question is; when we are in keytosis and we consume calories, does our bodies convert the calories into keytones that are used as fuel for energy?  And is it the calorie deficit that causes our bodies to burn fat reserves for the balance of the keytones needed to reach our calorie requirements for the day?