Energy balance
Fat-free mass-adjusted total and basal energy expenditure peaks at approximately 50% above adult levels around 1 year of age, then declines to adult baseline levels by age 20, remaining stable through age 60 before declining in older adults.
Your body's energy needs change predictably as you age. You burn significantly more energy relative to your size as a toddler (peaking around age 1) than as an adult. As you age from 20 to 60, your metabolic rate (adjusted for size) stabilizes. After 60, it declines. Do not assume your metabolic rate is constant or scales linearly with your weight; use age- and size-specific estimates for nutritional planning rather than simple weight-based ratios.
Fat-free mass–adjusted expenditure accelerates rapidly in neonates to ~50% above adult values at ~1 year; declines slowly to adult levels by ~20 years; remains stable in adulthood (20 to 60 years), even during pregnancy; then declines in older adults.
Why this rating
Large sample size (n=6421), diverse demographics (29 countries), and use of the gold-standard Doubly Labeled Water method.
Source
Daily energy expenditure through the human life course
Herman Pontzer et al. · Science · 2021
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