Does adaptive thermogenesis occur after weight loss in adults? A systematic review.
Level 1 - systematic review of randomized trials
Systematic review of experimental and observational follow-up studies
PubMed 33762040 · doi:10.1017/S0007114521001094
What was done
This systematic review (PROSPERO CRD42020165348) searched six databases (PubMed, Cochrane Library, EMBASE, MEDLINE, SCOPUS, Web of Science) through May 15, 2020. Included studies were experimental or observational follow-up studies in adults (age > 18 years, sample size ≥ 10, intervention ≥ 1 week) that produced statistically significant weight loss and objectively measured total daily energy expenditure (TDEE), resting energy expenditure (REE), or sleeping energy expenditure (SEE) with or without a weight stabilization phase. A total of 33 studies comprising 2,528 participants were included.
What was found
Adaptive thermogenesis (AT) was reported in 27 of 33 studies. Significant AT was found for REE in 23 studies (82.8%), for TDEE in 4 studies (80.0%), and for SEE in 2 studies (100%). However, well-designed studies reported lower or non-statistically significant AT values, and AT was attenuated or non-existent after periods of weight stabilization/neutral energy balance. High heterogeneity was reported across methods used to quantify AT and in the magnitude of weight loss and AT, but no pooled quantitative effect estimates or kcal/day figures were provided in the abstract.
Why it matters
This review demonstrates that while adaptive thermogenesis frequently occurs during active negative energy balance, it is attenuated or absent following weight stabilization and appears smaller in more rigorous studies. This challenges the notion that permanent, large reductions in metabolic rate inevitably undermine long-term weight maintenance.
Limits
The abstract reports only study counts and percentages without pooled effect sizes, confidence intervals, or precise kcal/day metrics. There was substantial heterogeneity in the methods used to calculate AT across studies. Included designs mixed observational and experimental protocols, and patient characteristics (such as baseline BMI or specific dietary interventions) were not detailed.
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- context Studies on yo-yo dieting and prolonged starvation periods show that they lower metabolic rate, which can lead to subsequent weight gain.