Metabolic Slowing with Massive Weight Loss despite Preservation of Fat-Free Mass
Metabolic Slowing with Massive Weight Loss despite Preservation of Fat-Free Mass
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DOI：
10.1210/jc.2012-1444
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发表时间：
2012-07-01
影响因子：
5.8
通讯作者：
Hall, Kevin D.
中科院分区：
文献类型：
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作者：
Johannsen, Darcy L.;Knuth, Nicolas D.;Hall, Kevin D.
背景：减肥过程中的一个重要目标是最大限度地减少脂肪，同时保持代谢活性无脂质量（FFM）。大规模的减肥通常会导致FFM的大量损失，从而可能减缓代谢率。目的：我们的目的是确定由饮食限制和剧烈运动组成的减肥计划是否有助于保持FFM和维持静息代谢率（RMR）。我们用双能X线吸收法测量身体成分，用间接量热法测量RMR，在基线（n = 16）、wk 6（n = 11）和wk 30（n = 16）时，用双标记水测定总能量消耗。（X +/- D;体重指数49.4 +/- 9.4 kg/m2），体脂49 +/- 5%。在第30周，超过三分之一的初始体重减轻（-38 +/-9%），其中17 +/-8%来自FFM，83 +/-8%来自脂肪。RMR的下降与体重的下降不成比例，证明了显著的代谢适应（第6周和第30周分别为-244 +/-231和-504 +/-171千卡/天，P < 0.01）。体力活动导致的能量消耗在第6周增加了10.2 +/- 5.1 kcal/kg.d，在第30周增加了6.0 +/- 4.1 kcal/kg.d（P < 0.001 vs. zero）.结论：尽管FFM相对保留，但运动并不能阻止静息代谢与体重减轻不成比例的显著减慢。这种代谢适应可能在体重维持期间持续存在，除非保持高水平的体力活动或热量限制，否则容易导致体重反弹。（临床内分泌代谢杂志97：2489-2496，2012）
Context: An important goal during weight loss is to maximize fat loss while preserving metabolically active fat-free mass (FFM). Massive weight loss typically results in substantial loss of FFM potentially slowing metabolic rate.Objective: Our objective was to determine whether a weight loss program consisting of diet restriction and vigorous exercise helped to preserve FFM and maintain resting metabolic rate (RMR).Participants and Intervention: We measured body composition by dual-energy x-ray absorptiometry, RMR by indirect calorimetry, and total energy expenditure by doubly labeled water at baseline (n = 16), wk 6 (n = 11), and wk 30 (n = 16).Results: At baseline, participants were severely obese (X +/- D; body mass index 49.4 +/- 9.4 kg/m(2)) with 49 +/- 5% body fat. At wk 30, more than one third of initial body weight was lost (-38 +/- 9%) and consisted of 17 +/- 8% from FFM and 83 +/- 8% from fat. RMR declined out of proportion to the decrease in body mass, demonstrating a substantial metabolic adaptation (-244 +/- 231 and -504 +/- 171 kcal/d at wk 6 and 30, respectively, P < 0.01). Energy expenditure attributed to physical activity increased by 10.2 +/- 5.1 kcal/kg.d at wk 6 and 6.0 +/- 4.1 kcal/kg.d at wk 30 (P < 0.001 vs. zero).Conclusions: Despite relative preservation of FFM, exercise did not prevent dramatic slowing of resting metabolism out of proportion to weight loss. This metabolic adaptation may persist during weight maintenance and predispose to weight regain unless high levels of physical activity or caloric restriction are maintained. (J Clin Endocrinol Metab 97: 2489-2496, 2012)