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Body Weight Homeostasis
➤ RMR has genetic variance, mainly via body mass-dependent
energy expenditure (i.e., individuals of male gender, increased
height, increased muscle, younger age and obesity typically
have higher RMR). An increase in fat free mass may not only
increase RMR, but may also increase hunger, which influences the
nutritional aspect of energy balance. Beyond RMR, other common
contributors to variances in energy expenditure include NEAT,
physical exercise, and thermogenesis of food. Finally, metabolic
rate (MR) can be affected by climate (hotter environment
increases MR to cool the body; colder environment increases MR
through non-shivering thermogenesis to warm the body).
Energy Expenditure: Components Overall
In individuals with moderate physical inactivity, components of
total energy expenditure:
• 70% resting MR
• 20% physical activity
• 10% diet-induced thermogenesis
With the exception of individuals engaged in physical exercise
outside typical study populations, the coefficient of variation in
humans regarding energy expenditure
a
:
• Resting MR = 10%
• Physical exercise = 2%
• Diet-induced thermogenesis = 20%
b
a
NEAT also contributes to variances in energ y expenditure.
b
Whole foods generally generate higher diet-induced thermogenesis than ultra-processed food.
