Total daily energy expenditure (“total expenditure”) reflects daily energy needs and is a critical variable in human health and physiology, but its trajectory over the life course is poorly studied. We analyzed a large, diverse database of total expenditure measured by the doubly labeled water method for males and females aged 8 days to 95 years. Total expenditure increased with fat-free mass in a power-law manner, with four distinct life stages. 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. These changes shed light on human development and aging and should help shape nutrition and health strategies across the life span.
Bibliographical noteThis is the author’s version of the work. It is posted here by permission of the AAAS for personal
use, not for redistribution. The definitive version was published in Science 373
13/08/2021, DOI: 10.1126/science.abe5017.
Funding Information: The IAEA Doubly Labeled Water (DLW) Database is generously supported by the IAEA, Taiyo Nippon Sanso, and SERCON. The authors also gratefully acknowledge funding from the US National Science Foundation (BCS-1824466) awarded to H.P. The funders played no role in the content of this manuscript.