Nutrition Science and Everyday Application - beta v 0.1

ENERGY BALANCE: ENERGY IN, ENERGY OUT—YET NOT AS SIMPLE AS IT SEEMS 373
Negative energy balance is when energy intake is less than energy expenditure, usually
resulting in weight loss.
Energy intake is made up of the calories we consume from food and beverages. These
calories come from the macronutrients (carbohydrates, proteins, and fats) and alcohol.
Remember that when the body has a surplus of energy, this energy can be stored as fat.
In theory, if you consume 3,500 more calories than your body needs, you could potentially
gain about one pound, because a pound of fat is equal to about 3,500 calories. If you expend
3,500 more calories than you take in, you could potentially lose about a pound, as your body
turns to this stored energy to compensate for the energy deficit. However, in practice, how
individuals respond to an excess or deficit of 3500 calories can be quite variable, and over
time, the body adapts to these conditions and resists changes in body weight.
Energy balance is complex, dynamic, and variable between individuals—something we’ll
explore a bit more later on this page—but it is still a vital concept in understanding body
weight. Next, let’s look at the energy expenditure side of the energy balance equation, to see
the components that make up energy expenditure and the factors that influence them.
COMPONENTS OF ENERGY EXPENDITURE
The sum of caloric expenditure is referred to as total energy expenditure (TEE).There are
three main components of TEE:
1. Basal metabolic rate (BMR)
2. Thermic effect of food (TEF)
3. Physical activity