How will a healthy individual’s atp production change during an eight-hour fast?

It will not be significantly altered.

Explanation:

During an eight-hour fast glycolisis and cellular respiration will continue to function normally and the production of ATP would not be altered significantly, because there is a source of energy-rich molecules used in catabolism from glycogen stored in muscles and the liver, or fats stored in the fatty tissue or the muscle's protein themselves that can be used as a source of energy.