when does the fat burning process actually happen?

Question

I was told that you break down muscle fibers with resistance training and build the muscles back when you sleep (provided you have enough protein). What about fat burning? Do you burn fat while you work out? Sleep? I understand you lose weight when there is a calorie deficit but when does it actually happen?

In: Biology

Answer 1

When you breathe.

Every moment of the day you have constant metabolism of tissues and storage of tissues.

CO2 is generated from using those stores of fat for energy.

So you have to breathe it off.

This is a very very Eli5 response. I have a bachelor’s in exercise physiology and doctorate in physical therapy.