Background

Adaptive thermogenesis during prolonged energy deficit refers to the greater than expected reduction in energy expenditure (EE) independent of concomitant loss of metabolically active body mass.

Objective

As inter-individual variability in the magnitude of adaptive thermogenesis may influence the extent of energy deficit thereby predicting the amount of weight reduction, we investigated whether early adaptive thermogenesis is a determinant of weight loss after 6 weeks of daily 50% caloric restriction in an inpatient setting.

Design and methods

The current study reports the results of an exploratory, secondary analysis in overweight but otherwise healthy subjects (n = 11, 7 men, 35 ± 9y, BMI = 40 ± 7 kg/m², body fat = 63.3 ± 5.3%). Body composition and 24-h EE (24hEE) measurement in a whole-room indirect calorimeter were used to calculate the magnitude of adaptive thermogenesis while on caloric restriction after 1, 3 and 6 weeks. Energy deficit during caloric restriction was quantified via food, stool, and urine bomb calorimetry. Fasting hormonal concentrations (FT4, FT3, FGF21, leptin) were obtained at baseline and at weeks 3 and 6 during caloric restriction.

Results

The magnitude of adaptive thermogenesis in 24hEE after 1 week of caloric restriction was −178 ± 137 kcal/day (mean ± SD), was overall stable during and following caloric restriction, and demonstrated remarkable intra-individual consistency. A relatively greater decrease in 24hEE of 100 kcal/d after 1 week of caloric restriction was associated on average with reduced energy deficit by 8195 kcal over 6 weeks and predicted 2.0 kg less weight loss, of which 0.5 kg was fat mass, after 6 weeks. No correlations were found between hormonal concentrations and weight loss.

Conclusions

The extent of weight loss is influenced by the magnitude of adaptive thermogenesis in the early stage of caloric restriction. Although these results need replication in larger study groups with adequate statistical power, targeting adaptive thermogenesis may help to optimize long-term interventions in obesity therapy.

中文翻译：

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早期适应性产热是超重受试者在限制热量摄入六周后体重减轻的决定因素。

背景

长期能量缺乏期间的适应性产热是指能量消耗 (EE) 的减少幅度大于预期，而与代谢活跃体重的伴随损失无关。

客观的

由于适应性生热程度的个体差异可能会影响能量缺乏的程度，从而预测体重减轻的程度，我们研究了早期适应性生热是否是住院患者每天 50% 热量限制 6 周后体重减轻的决定因素环境。

设计和方法

目前的研究报告了对超重但其他方面健康的受试者（n  = 11，7 名男性，35 ± 9 岁，BMI = 40 ± 7 kg/m ²，体脂 = 63.3 ± 5.3%）的探索性二次分析结果。身体成分和 24 小时 EE (24hEE) 在整个房间间接热量计中的测量用于计算 1、3 和 6 周后热量限制时适应性产热的大小。热量限制期间的能量缺乏通过食物、粪便和尿液炸弹量热法进行量化。空腹激素浓度（FT4、FT3、FGF21、瘦素）是在基线和热量限制期间的第 3 周和第 6 周获得的。

结果

热量限制 1 周后 24hEE 中适应性产热的幅度为 -178 ± 137 kcal/天（平均值 ± SD），在热量限制期间和之后总体稳定，并且表现出显着的个体内一致性。热量限制 1 周后 100 kcal/d 的 24hEE 下降幅度相对较大，这与 6 周内能量缺乏平均减少 8195 kcal 相关，并预测 6 周后体重减轻 2.0 kg，其中 0.5 kg 是脂肪量. 荷尔蒙浓度与体重减轻之间没有发现相关性。

结论

在热量限制的早期阶段，体重减轻的程度受适应性产热的大小的影响。尽管这些结果需要在具有足够统计能力的大型研究组中进行复制，但针对适应性产热可能有助于优化肥胖治疗的长期干预措施。