60% of the calories the body takes in is used for body functions, or basal metabolic rate (B.M.R.), such as: heart rate, breathing, kidney and liver functions, ect.
10% of the calories the body takes in is used for diet induced thermogenesis- a fancy way to say digestion.
30% of the calories the body takes in is used for all the physical activity the body does such as: exercise, eating, drinking, driving, reading, sleeping, watching TV, talking, typing, etc.
The more fit a person is, the higher his/her B.M.R. will be requiring more calories.
S.A.I.D - Specific Adaptations to Imposed Demands.
If you are active, the body will adapt
If you are sedentary, the body will adapt.