Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
J Hum Nutr Diet. 2011 Dec;24(6):525-35. doi: 10.1111/j.1365-277X.2011.01203.x. Epub 2011 Sep 7.
Obesity is highly prevalent throughout the world. Although modified-carbohydrate diets (MCDs) comprise one popular approach, questions remain about their utility for weight loss. The objective of the present study was to conduct a meta-analysis of randomised controlled trials (RCTs) of a specific MCD compared with various control diets on weight loss.
Data from four RCTs (three obtained from the sponsor and one indentified through literature searches) were included. Intent-to-treat analyses were conducted using multiple imputation to handle missing data, where possible. Because inter-study heterogeneity was demonstrated with fixed-effects meta-analysis, a random-effects meta-analysis also was conducted.
When considered separately, all four studies showed greater reduction in body weight with the MCD compared to control diets at 12-week follow-up; the results at 24 weeks (available for three of the studies) were not as consistent. Results for body mass index (BMI) were similar. Greater reductions in waist circumference with the MCD were seen at either time point in only one study. When fixed-effects meta-analysis was applied, significantly greater reductions in weight, BMI and waist circumference with the MCD at both 12 weeks (1.66 kg, 0.53 kg m(-2) and 1.02 cm, respectively) and 24 weeks (1.20 kg, 0.43 kg m(-2) and 0.69 cm, respectively) were evident. Random-effects meta-analysis revealed similar results; however, the 24-week difference for a reduction in waist circumference was no longer statistically significant.
Meta-analysis of individual RCT results demonstrated consistent benefits of this MCD compared to control diets on weight loss up to 24 weeks and waist circumference up to 12 weeks.
肥胖在全球范围内普遍存在。虽然改良碳水化合物饮食（MCD）是一种流行的方法，但关于其减肥效果仍存在疑问。本研究的目的是对特定 MCD 与各种对照饮食在减肥方面的随机对照试验（RCT）进行荟萃分析。
纳入了四项 RCT 的数据（其中三项从赞助商处获得，一项通过文献检索确定）。尽可能使用多重插补处理缺失数据进行意向治疗分析。由于固定效应荟萃分析显示研究间存在异质性，因此还进行了随机效应荟萃分析。
当分别考虑时，四项研究均显示在 12 周随访时，MCD 组体重较对照组显著减轻；但在 24 周时（三项研究中仅其中三项可获得）结果并不一致。体重指数（BMI）的结果相似。仅在一项研究中，MCD 组在两个时间点均观察到腰围的更大减少。当应用固定效应荟萃分析时，MCD 在 12 周（体重减少 1.66 公斤，BMI 减少 0.53 公斤/米²，腰围减少 1.02 厘米）和 24 周（体重减少 1.20 公斤，BMI 减少 0.43 公斤/米²，腰围减少 0.69 厘米）时体重、BMI 和腰围的减少均显著更大。随机效应荟萃分析显示出相似的结果；然而，24 周时腰围减少的差异不再具有统计学意义。
对个体 RCT 结果的荟萃分析表明，与对照饮食相比，这种 MCD 在 24 周内和 12 周内的减肥和腰围减少方面均具有一致的益处。
