Bosy-Westphal Anja, Kossel Elke, Goele Kristin, Later Wiebke, Hitze Britta, Settler Uta, Heller Martin, Glüer Claus-Christian, Heymsfield Steven B, Müller Manfred J
Institute of Human Nutrition and Food Science, Christian-Albrechts University, Kiel, Germany.
Am J Clin Nutr. 2009 Oct;90(4):993-1001. doi: 10.3945/ajcn.2008.27402. Epub 2009 Aug 26.
Weight loss leads to reduced resting energy expenditure (REE) independent of fat-free mass (FFM) and fat mass (FM) loss, but the effect of changes in FFM composition is unclear.
We hypothesized that a decrease in REE adjusted for FFM with weight loss would be partly explained by a disproportionate loss in the high metabolic activity component of FFM.
Forty-five overweight and obese women [body mass index (in kg/m(2)): 28.7-46.8] aged 22-46 y followed a low-calorie diet for 12.7 +/- 2.2 wk. Body composition was measured by magnetic resonance imaging, dual-energy X-ray absorptiometry, and a 4-compartment model. REE measured by indirect calorimetry (REEm) was compared with REE calculated from detailed body-composition analysis (REEc) by using specific organ metabolic rates (ie, organ REE/mass).
Weight loss was 9.5 +/- 3.4 kg (8.0 +/- 2.9 kg FM and 1.5 +/- 3.1 kg FFM). Decreases in REE (-8%), free triiodothyronine concentrations (-8%), muscle (-3%), heart (-5%), liver (-4%), and kidney mass (-6%) were observed (all P < 0.05). Relative loss in organ mass was significantly higher (P < 0.01) than was the change in low metabolically active FFM components (muscle, bone, and residual mass). After weight loss, REEm - REEc decreased from 0.24 +/- 0.58 to 0.01 +/- 0.44 MJ/d (P = 0.01) and correlated with the decrease in free triiodothyronine concentrations (r = 0.33, P < 0.05). Women with high adaptive thermogenesis (defined as REEm - REEc < -0.17 MJ/d) had less weight loss and conserved FFM, liver, and kidney mass.
After weight loss, almost 50% of the decrease in REEm was explained by losses in FFM and FM. The variability in REEm explained by body composition increased to 60% by also considering the weight of individual organs.
体重减轻会导致静息能量消耗（REE）减少，且这种减少与去脂体重（FFM）和脂肪量（FM）的减少无关，但FFM组成变化的影响尚不清楚。
我们假设，体重减轻后经FFM调整的REE下降部分可由FFM中高代谢活性成分的不成比例减少来解释。
45名年龄在22 - 46岁的超重和肥胖女性[体重指数（kg/m²）：28.7 - 46.8]遵循低热量饮食12.7±2.2周。通过磁共振成像、双能X线吸收法和四成分模型测量身体成分。通过间接测热法测得的REE（REEm）与使用特定器官代谢率（即器官REE/质量）从详细身体成分分析计算得出的REE（REEc）进行比较。
体重减轻9.5±3.4 kg（FM减少8.0±2.9 kg，FFM减少1.5±3.1 kg）。观察到REE下降（-8%）、游离三碘甲状腺原氨酸浓度下降（-8%）、肌肉量下降（-3%）、心脏量下降（-5%）、肝脏量下降（-4%）和肾脏量下降（-6%）（所有P<0.05）。器官质量的相对损失显著高于低代谢活性FFM成分（肌肉、骨骼和剩余质量）的变化（P<0.01）。体重减轻后，REEm - REEc从0.24±0.58降至0.01±0.44 MJ/d（P = 0.01），并与游离三碘甲状腺原氨酸浓度的下降相关（r = 0.33，P<0.05）。适应性产热高的女性（定义为REEm - REEc < -0.17 MJ/d）体重减轻较少，且保留了FFM、肝脏和肾脏质量。
体重减轻后，REEm下降的近50%可由FFM和FM的减少来解释。通过考虑各个器官的重量，身体成分对REEm变化的解释率增加到60%。
