Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight.
Level 4 - case-series / case-control
Matched cross-sectional comparative physiological study.
PubMed 18842775 · doi:10.1093/ajcn/88.4.906
What was done
In an inpatient setting, investigators studied 7 sex- and weight-matched trios (21 subjects total) receiving an identical weight-maintaining liquid formula diet. Each trio comprised: one subject at usual weight (Wt(initial)), one subject maintaining a >=10% weight reduction 5 to 8 weeks after weight loss (Wt(loss-recent)), and one subject who had maintained a documented >10% weight reduction for >1 year (Wt(loss-sustained)). Total energy expenditure (TEE) was measured over 24 hours by titrating calories to maintain stable weight. Resting energy expenditure (REE) and the thermic effect of feeding (TEF) were measured by indirect calorimetry, and nonresting energy expenditure (NREE) was calculated by subtraction.
What was found
TEE, NREE, and to a lesser extent REE were significantly lower in both the recent weight loss group and the sustained weight loss group compared with the usual weight control group. The reductions relative to controls were reported to be qualitatively and quantitatively similar between recent and sustained weight maintainers. Specific numerical values, effect sizes, and exact p-values were not reported in the abstract.
Why it matters
The findings indicate that adaptive thermogenesis—the disproportionate reduction in energy expenditure following weight loss—does not resolve with prolonged weight stability, providing a physiological explanation for the persistent difficulty of long-term weight-loss maintenance.
Limits
The sample size is small (7 trios, 21 participants). The study compared matched individuals cross-sectionally rather than tracking a single longitudinal cohort before, immediately after, and >1 year after weight loss. Inpatient liquid-formula feeding may not fully capture free-living metabolic and behavioral variability, and the abstract omits quantitative point estimates and variance metrics.
Cited by
- partial Losing 10% of body weight can induce a 400 to 500 calorie decrease in non-exercise activity thermogenesis (NEAT) per day.