Weinsier R L, Nagy T R, Hunter G R, Darnell B E, Hensrud D D, Weiss H L
Departments of Nutrition Sciences and Human Studies, the General Clinical Research Center, University of Alabama at Birmingham, and the Mayo Clinic, Rochester, MN, USA.
Am J Clin Nutr. 2000 Nov;72(5):1088-94. doi: 10.1093/ajcn/72.5.1088.
Obese persons generally regain lost weight, suggesting that adaptive metabolic changes favor return to a preset weight.
Our objective was to determine whether adaptive changes in resting metabolic rate (RMR) and thyroid hormones occur in weight-reduced persons, predisposing them to long-term weight gain.
Twenty-four overweight, postmenopausal women were studied at a clinical research center in four 10-d study phases: the overweight state (phase 1, energy balance; phase 2, 3350 kJ/d) and after reduction to a normal-weight state (phase 3, 3350 kJ/d; phase 4, energy balance). Weight-reduced women were matched with 24 never-overweight control subjects. After each study phase, assessments included RMR (by indirect calorimetry), body composition (by hydrostatic weighing), serum triiodothyronine (T(3)), and reverse T(3) (rT(3)). Body weight was measured 4 y later, without intervention.
Body composition-adjusted RMR and T(3):rT(3) fell during acute (phase 2) and chronic (phase 3) energy restriction (P: < 0.01), but returned to baseline in the normal-weight, energy-balanced state (phase 4; mean weight loss: 12.9 +/- 2.0 kg). RMR among weight-reduced women (4771 +/- 414 kJ/d) was not significantly different from that in control subjects (4955 +/- 414 kJ/d; P: = 0.14), and lower RMR did not predict greater 4-y weight regain (r = 0.27, NS).
Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions. Failure to establish energy balance after weight loss gives the misleading impression that weight-reduced persons are energy conservative and predisposed to weight regain. Our findings do not provide evidence in support of adaptive metabolic changes as an explanation for the tendency of weight-reduced persons to regain weight.
肥胖者通常会重新增加已减轻的体重，这表明适应性代谢变化有利于体重恢复到预设水平。
我们的目的是确定体重减轻的人静息代谢率（RMR）和甲状腺激素是否会发生适应性变化，使他们易于长期体重增加。
24名超重的绝经后女性在一个临床研究中心接受了四个为期10天的研究阶段：超重状态（第1阶段，能量平衡；第2阶段，3350千焦/天）以及减重至正常体重状态后（第3阶段，3350千焦/天；第4阶段，能量平衡）。体重减轻的女性与24名从未超重的对照受试者进行匹配。每个研究阶段后，评估包括RMR（通过间接测热法）、身体成分（通过水下称重）、血清三碘甲状腺原氨酸（T(3)）和反三碘甲状腺原氨酸（rT(3)）。4年后在无干预的情况下测量体重。
在急性（第2阶段）和慢性（第3阶段）能量限制期间，经身体成分调整的RMR和T(3):rT(3)下降（P：＜0.01），但在正常体重、能量平衡状态下（第4阶段；平均体重减轻：12.9±2.0千克）恢复到基线水平。体重减轻女性的RMR（4771±414千焦/天）与对照受试者（4955±414千焦/天；P：=0.14）无显著差异，较低的RMR并未预测4年后更大的体重反弹（r = 0.27，无显著性）。
能量限制会产生一种短暂的甲状腺功能减退-低代谢状态，在恢复到能量平衡状态时会恢复正常。体重减轻后未能建立能量平衡会给人一种误导性的印象，即体重减轻的人能量消耗少且易于体重反弹。我们的研究结果并未提供证据支持适应性代谢变化可解释体重减轻者体重反弹的倾向。
