What is used to estimate total energy needs by multiplying resting metabolic rate by a factor?

• A. Body mass index
• B. Thermic effect of food
• C. Physical activity factor
• D. Resting metabolic rate multiplier

Answer: (C)

Estimating total daily energy needs relies on taking the energy your body uses at rest and scaling it up to reflect daily activity. Resting metabolic rate provides the baseline energy need, and the multiplier used to adjust that baseline for daily activity is the physical activity factor. Different activity levels (sedentary, lightly active, moderately active, very active, etc.) have corresponding multipliers, which when applied to the resting rate give the total energy expenditure.

The thermic effect of food is a separate, smaller component of energy use and isn’t the multiplier used to estimate total energy needs. BMI is a measure of body size, not energy requirements. A “resting metabolic rate multiplier” isn’t the standard term used in practice; the established idea is to multiply RMR by the physical activity factor to arrive at total energy needs.