Wadden T A, Considine R V, Foster G D, Anderson D A, Sarwer D B, Caro J S
University of Pennsylvania School of Medicine, Department of Psychiatry, Philadelphia, USA.
J Clin Endocrinol Metab. 1998 Jan;83(1):214-8. doi: 10.1210/jcem.83.1.4494.
This study examined the effects of caloric restriction and weight loss on serum leptin concentrations in 49 obese women who participated in a 40-week weight loss program. During the first 12 weeks, half the subjects were provided a 1000 kcal/day low-calorie diet (LCD), compromised of portion-controlled foods, whereas the other half were prescribed a 1200 kcal/day balanced deficit diet (BDD) consisting of self-selected table foods. Thereafter, subjects in both conditions were instructed to consume approximately 1200-1800 kcal/day of self-selected foods, depending on their desired weight change. During the first 6 weeks, weight and serum leptin fell significantly more (P < 0.05) in women in the LCD condition than in the BDD condition. In the former group, the 55% reduction in baseline leptin was 10 times greater than the relative reduction in body weight. Stepwise multiple regression analysis revealed that degree of caloric restriction, but not weight loss, contribution significantly to the variance in the change in leptin at week 6. By contrast, long-term changes in leptin, when subjects had increased their calorie intake, were more strongly related to changes in weight and fat. At week 40, for example, weight loss account for 47% of the variance in the change in leptin. Serum leptin and body fat remained highly correlated after weight loss (r = 0.79, P < 0.001), as before (r = 0.66, P < 0.001). After treatment, however, we observed a greater-than-expected reduction in serum leptin concentrations, as expressed per kilogram of body fat. The significance of this finding remains to be determined.
本研究调查了热量限制和体重减轻对49名参与为期40周减肥计划的肥胖女性血清瘦素浓度的影响。在最初的12周里，一半受试者食用由定量控制食物组成的1000千卡/天低热量饮食（LCD），而另一半则被规定食用由自选日常食物组成的1200千卡/天平衡亏空饮食（BDD）。此后，两种情况下的受试者都被指示根据其期望的体重变化，食用约1200 - 1800千卡/天的自选食物。在最初的6周里，处于LCD状态的女性体重和血清瘦素下降幅度明显更大（P < 0.05），大于处于BDD状态的女性。在前一组中，基线瘦素降低55%，是体重相对降低幅度的10倍。逐步多元回归分析显示，热量限制程度而非体重减轻，对第6周瘦素变化的方差有显著贡献。相比之下，当受试者增加热量摄入时，瘦素的长期变化与体重和脂肪的变化更密切相关。例如，在第40周时，体重减轻占瘦素变化方差的47%。体重减轻后，血清瘦素与体脂仍保持高度相关（r = 0.79，P < 0.001），与之前一样（r = 0.66，P < 0.001）。然而，治疗后，我们观察到血清瘦素浓度按每千克体脂计算的降低幅度大于预期。这一发现的意义仍有待确定。
