Background: Cocoa and dark chocolate (DC) have been reported to be effective for health promotion; however the exact effect of cocoa/DC on anthropometric measures have not been yet defined. Methods: A comprehensive search to identify randomized clinical trials investigating the impact of cocoa/DC on body weight, body mass index (BMI) and waist circumference (WC) was performed up to December 2017. A meta-analysis of eligible studies was performed using random effects model to estimate pooled effect size. Fractional polynominal modeling was used to explore dose-response relationships. Results: A total of 35 RCTs investigated the effects of cocoa/DC on weight, BMI and WC were included. Meta-analysis did not suggest any significant effect of cocoa/DC supplementation on body weight (−0.108 kg, 95% CI −0.262, 0.046 P = 0.168), BMI (−0.014 kg/m² 95% CI −0.105, 0.077, P: 0.759,) and WC (0.025 cm 95% CI −0.083, 0.129, P = 0.640). Subgroup analysis revealed that that weight and BMI were reduced with cocoa/DC supplementation ≥ 30 g chocolate per day in trials between 4-8 weeks. Cocoa/DC consumption resulted in WC reduction in non-linear fashion (r = 0.042, P-nonlinearity = 0.008).Conclusion: Cocoa/DC supplementation does not reduce anthropometric measures significantly. However subgroup analysis regarding dose (≥ 30 g/day) and duration (between 4 to 8 weeks) revealed significant reduction of body weight and BMI.

中文翻译：

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可可/黑巧克力补充剂对体重，体重指数和腰围有良好的作用吗？随机临床试验的系统评价，荟萃分析和剂量反应

背景：据报道可可和黑巧克力（DC）对健康促进有效；然而，可可/ DC对人体测量的确切作用尚未确定。方法：截至2017年12月，进行全面搜索以鉴定调查可可/ DC对体重，体重指数（BMI）和腰围（WC）的影响的随机临床试验。随机效应模型来估计合并效应的大小。分数多项式建模用于探索剂量反应关系。结果：共有35个RCT研究了可可/ DC对体重，BMI和WC的影响。荟萃分析未显示可可/ DC补充对体重（-0.108 kg，95％CI -0.262，0.046 P = 0.168），BMI（-0.014 kg / m ² 95％CI -0.105，0.077， P：0.759，）和WC（0.025cm 95％CI -0.083，0.129，P ＝ 0.640）。亚组分析显示，在4至8周的试验中，每天可可/ DC补充量≥30 g巧克力可减轻体重和BMI。可可/ DC消耗以非线性方式导致WC降低（r = 0.042，P非线性= 0.008）。结论：可可/ DC补充剂不会显着减少人体测量指标。然而，关于剂量（≥30 g /天）和持续时间（4至8周）的亚组分析显示，体重和BMI显着降低。