Bibliographic record
Abstract
It is well established that substantial body fat loss in individuals with obesity can induce a state of metabolic vulnerability potentially favoring long-term weight regain. This is explained by a greater than predicted decrease in energy expenditure and an increase in appetite that are associated with biological adaptations such as reduced leptinemia and sympathetic nervous system activity (1, 2). However, despite the numerous research attempts to determine whether cycles of weight loss/regain may generate persistent metabolic vulnerability, this question has never been clearly answered and remains a significant matter of preoccupation for health professionals and individuals with obesity. In this issue of Obesity, Fothergill et al. (3) report a study that gave the opportunity to test participants of “The Biggest Loser” in whom resting metabolic rate (RMR) was measured before and after the competition as well as 6 years later. As expected, the mean 58.3 kg weight loss observed during the competition resulted in a substantial decrease in RMR that reached 610 kcal/day. These investigators also estimated that this decrease included a metabolic adaptation of 275 kcal/day representing a decrease exceeding what would have been predicted by the loss of fat mass and fat-free mass. Six years after the end of the competition, this decrease in adaptive thermogenesis was even more pronounced. The mean metabolic adaptation had increased to 499 kcal/day, which explains why RMR remained 704 kcal/day below the baseline level despite a 41 kg body weight regain. As described by the investigators, this large metabolic adaptation could not be attributed to the fact that RMR was measured with a different calorimeter 6 years after the end of the competition. Additionally, our research experience reveals that the reported persistent metabolic adaptation can only be partly attributable to an aging effect over a 6-year follow-up (4). Globally, the results of this study are well concordant with previous long-term studies having shown that substantial weight loss induces biological adaptations that promote weight regain (1, 2). Beyond these observations, the results of this study add bad news to this story which is related to the amplification of the metabolic adaptation over time. From a clinical standpoint, this should be viewed as an important argument in favor of the inclusion of weight maintenance periods within a weight-reducing program that could reveal that a healthy sustainable body weight is achieved and that striving for maximal weight loss is not relevant. Finally, the reported thermogenic adaptation over time also reminds us that the metabolic vulnerability of individuals with obesity persists even after their condition has supposedly been cured by weight loss.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.018 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.004 | 0.012 |
| Scholarly communication | 0.010 | 0.022 |
| Open science | 0.004 | 0.005 |
| Research integrity | 0.015 | 0.033 |
| Insufficient payload (model declined to judge) | 0.016 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".