Daily energy expenditure through the human life course.
Level 4 - case-series / case-control
Cross-sectional database analysis of physiological measurements across age cohorts
PubMed 34385400 · doi:10.1126/science.abe5017
What was done
Authors analyzed a large, diverse database of total daily energy expenditure measured by the doubly labeled water method in males and females aged 8 days to 95 years to identify metabolic trajectories across the lifespan.
What was found
Total expenditure increased with fat-free mass in a power-law relationship across four distinct life stages: - Fat-free mass-adjusted expenditure accelerates rapidly in neonates to ~50% above adult values at ~1 year. - It slowly declines to adult levels by ~20 years. - It remains stable in adulthood from 20 to 60 years, including during pregnancy. - It declines in older adults (>60 years). Absolute expenditure values and exact sample size are not reported in the abstract.
Why it matters
These findings challenge the assumption of a continuous midlife metabolic slowdown, demonstrating that tissue-level energy expenditure is stable from ages 20 to 60 and peaks dramatically in early infancy.
Limits
The abstract does not state the total sample size, participant demographics, health status, or geographical distribution. As a pooled cross-sectional analysis, it cannot track individual longitudinal trajectories.
Cited by
- supports Basal metabolic rate does not significantly decrease during young-to-middle adulthood.
- contradicts Newborn infants have lower energy expenditure per unit of body weight compared to adults.
- partial Human energy expenditure per unit of body weight peaks around age 5, declines until roughly age 20, remains flat across adulthood, and begins declining around age 70.