Dulloo A G, Girardier L
Department of Physiology, University of Geneva, Switzerland.
Int J Obes Relat Metab Disord. 1993 Feb;17(2):115-23.
The existence and quantitative contribution of an adaptive increase in whole-body metabolic efficiency in response to low caloric intake was examined after prolonged underfeeding in the rat. 24h energy expenditures (EE) and body composition were measured in chronically underfed rats which had been maintaining a stable body weight for several months after an initial period of substantial weight loss. Comparisons were made with ad libitum fed controls. The mean coefficient of variation for daily EE, assessed over three consecutive days, was 3% (range 1.7-4.0%) in the control group and 1.6% (range 0.7-2.1%) in the chronically underfed group, and hence reflect steady state conditions. Body composition was determined by chemical analysis, and as a proportion of body weight (BW), the fat content in the underfed group was reduced by 40% whereas lean body mass was significantly higher by 8%. Independently of the criteria utilized for metabolically active mass, 24h EE was lower in the underfed group than in controls, by 17%, 14% and 8% as a function of BW0.66, BW0.75 and lean body mass respectively (P < 0.01). Underfeeding was also associated with a substantial reduction in the level of external work, but in ad libitum fed animals similar reductions in external work (induced by limiting locomotion) failed to alter 24h EE significantly. Taken together, these studies provide evidence for an increased metabolic efficiency in response to low calorie intake well beyond the period of dynamic weight loss.
在大鼠长期进食不足后，研究了机体对低热量摄入的适应性增加所带来的全身代谢效率提高的存在情况及其定量贡献。对长期进食不足且在最初体重显著下降后已维持稳定体重数月的大鼠，测量其24小时能量消耗（EE）和身体组成。并与自由进食的对照组进行比较。连续三天评估的每日EE平均变异系数，对照组为3%（范围1.7 - 4.0%），长期进食不足组为1.6%（范围0.7 - 2.1%），这反映了稳定状态。通过化学分析确定身体组成，以体重（BW）的比例计算，进食不足组的脂肪含量减少了40%，而瘦体重显著增加了8%。无论用于代谢活跃质量的标准如何，进食不足组的24小时EE均低于对照组，分别以BW0.66、BW0.75和瘦体重为函数时，降低了17%、14%和8%（P < 0.01）。进食不足还与外部功水平的大幅降低有关，但在自由进食的动物中，类似的外部功降低（通过限制运动诱导）并未显著改变24小时EE。综上所述，这些研究为低热量摄入后代谢效率提高提供了证据，且这种提高远远超出了动态体重减轻的时期。
