美国芝加哥大学的一项小规模研究显示，节食者缺少睡眠不利减肥，这项研究日前发表在《内科学年鉴》上。
这项研究的研究对象为10名超重男女，他们先后入住睡眠实验室两次，每次为期两周。被试者在两期实验中减肥食谱相同，但一期实验每晚睡眠时间为八个半小时，另一期实验每晚只睡五个半小时。研究人员发现，节食者在两次实验中平均减肥都将近7磅。不过，在睡眠较少的阶段，被试者减轻的主要是肌肉而非脂肪；在每晚睡八个半小时的实验阶段，被试者减掉的半数以上重量是脂肪。因此，专家建议减肥者应保证每晚睡眠时间充足。
推荐原文出处：
Ann Intern Med doi:10.1059/0003-4819-153-7-201010050-00006
Insufficient Sleep Undermines Dietary Efforts to Reduce Adiposity
Arlet V. Nedeltcheva, MD; Jennifer M. Kilkus, MS; Jacqueline Imperial, RN; Dale A. Schoeller, PhD; and Plamen D. Penev, MD, PhD
Abstract
Background: Sleep loss can modify energy intake and expenditure.
Objective: To determine whether sleep restriction attenuates the effect of a reduced-calorie diet on excess adiposity.
Design: Randomized, 2-period, 2-condition crossover study.
Setting: University clinical research center and sleep laboratory.
Patients: 10 overweight nonsmoking adults (3 women and 7 men) with a mean age of 41 years (SD, 5) and a mean body mass index of 27.4 kg/m2 (SD, 2.0).
Intervention: 14 days of moderate caloric restriction with 8.5 or 5.5 hours of nighttime sleep opportunity.
Measurements: The primary measure was loss of fat and fat-free body mass. Secondary measures were changes in substrate utilization, energy expenditure, hunger, and 24-hour metabolic hormone concentrations.
Results: Sleep curtailment decreased the proportion of weight lost as fat by 55% (1.4 vs. 0.6 kg with 8.5 vs. 5.5 hours of sleep opportunity, respectively; P = 0.043) and increased the loss of fat-free body mass by 60% (1.5 vs. 2.4 kg; P = 0.002). This was accompanied by markers of enhanced neuroendocrine adaptation to caloric restriction, increased hunger, and a shift in relative substrate utilization toward oxidation of less fat.
Limitation: The nature of the study limited its duration and sample size.
Conclusion: The amount of human sleep contributes to the maintenance of fat-free body mass at times of decreased energy intake. Lack of sufficient sleep may compromise the efficacy of typical dietary interventions for weight loss and related metabolic risk reduction.
