Physical activity amounts to about 20 to 30 percent of the body’s total energy output. Energy expended during physical activity varies with the level and duration of the activity. It is also affected by the age, gender, height, and weight of the individual performing the activity
.The relationship between the calories you take in through food and drinks, and the calories you burn through physical activity and basic functions (like breathing and digestion) is your energy balance.
You’ll have either a positive energy balance, a negative energy balance, or a perfect balance. Perfect Balance: If you end up with a 0 at the end of your energy equation, you’ve found a perfect energy balance.
A positive energy balance, in which energy intake exceeds expenditure causes weight gain, with 60–80 % of the resulting weight gain being attributable to body fat.