Specific Dynamic Action (SDA) of Food
Start with the big picture
SDA is the energy cost of digesting, absorbing, transporting, metabolizing, and storing nutrients. It is measured as the difference between post-meal and fasting metabolic rate under thermoneutral rest. A typical mixed diet’s SDA is about 10% of daily energy expenditure, though it varies with diet and individual factors; a mixed meal expends an average of 5–10 kcal per 100 kcal consumed. Protein has the greatest SDA, followed by alcohol, carbohydrates, and fats. SDA is influenced by sympathetic activity and brown adipose tissue thermogenesis, and it should be considered alongside basal metabolic rate and physical activity when estimating energy needs. It is distinct from hormonal calorigenic effects and energy lost in feces or urine.
What you'll learn
- Define SDA and identify its alternative names.
- Describe SDA’s approximate contribution to energy expenditure and how it varies by nutrient.
- Explain the metabolic processes and physiological mechanisms that contribute to SDA.
- Identify factors that can increase or reduce SDA.
- Distinguish SDA from other sources of energy expenditure or energy loss.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
