12
Evaluation
TOP 10 TAKEAWAY MESSAGES:
Obesity and Energy Expenditure
1. For most individuals, RMR represents ~70% of total daily energy
expenditure.
2. For most individuals without excess body fat, skeletal muscle,
liver, brain, heart, and digestive system each account for
~10–20% of RMR (~75% of total RMR). Kidney, adipose tissue, and
remaining/residual = ~25%.
3. Non-exercise activity thermogenesis (NEAT) varies among
individuals, can range between 150–500 kcal/day (often greater
than bouts of physical exercise), and can help account for the
perception that some individuals more easily maintain a healthy
body weight despite similar caloric intake and dedicated physical
exercise.
4. Direct calorimetry estimates energy expenditure via measurement
of heat generated by an organism in an enclosed chamber.
5. Indirect calorimetry estimates energy expenditure by measuring
carbon dioxide production and oxygen consumption using a
metabolic cart or a portable device.
6. Resting energy expenditure can be estimated by calculations
(Harris-Benedict and Mifflin St. Jeor Equations).
7. Doubly labeled water (used primarily in research settings)
estimates energy expenditure via oral administration of
traceable hydrogen and oxygen isotope, and the estimation of
carbon dioxide production, reflecting energy expenditure due to
tissue respiration.
8. Physical activity expenditure can be estimated by wearable
technologies, such as pedometers and accelerometers.
9. Energy expenditure may increase with inefficiencies in
physiologic and behavior processes.
10. In addition to physical exercise, increased energy expenditure
can be achieved via increased leisure time physical activity and
NEAT.
