Nutrition Science and Everyday Application - beta v 0.1

Energy Balance: Energy In, Energy Out—Yet
Not As Simple As It Seems
The concept of energy balance seems simple on paper. Balance the calories you consume
with the calories you expend. But many factors play a role in energy intake and energy
expenditure. Some of these factors are under our control and others are not. In this section,
we will define energy balance, look at the different components of energy expenditure, and
discuss the factors that influence energy expenditure. We’ll also consider some of the factors
that affect energy intake and consider why energy balance is more complex than it seems.
ENERGY BALANCE
Our body weight is influenced by our energy intake (calories we consume) and our energy
output (energy we expend during rest and physical activity). This relationship is defined by
the energy balance equation:
Energy Balance = energy intake – energy expenditure
When an individual is in energy balance, energy intake equals energy expenditure, and
weight should remain stable.
Positive energy balance occurs when energy intake is greater than energy expenditure,
usually resulting in weight gain.
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