BACKGROUND Caffeine is frequently added to dietary supplements with claims it facilitates weight loss. OBJECTIVE The purpose of this study was to test the hypothesis that caffeine administration reduces laboratory and free-living food intake by reducing appetite and that these effects vary by body mass index (BMI). PARTICIPANTS/SETTING Fifty adults aged 18 to 50 years completed the study (42% male). Exclusion criteria included no previous experience with caffeine, previous adverse event following caffeine consumption, taking any medications or having a medical condition contraindicating caffeine or stimulant consumption or affecting appetite or eating, and reported tobacco use within the past 6 months. DESIGN AND INTERVENTION Participants visited the laboratory on four separate occasions to complete a double-blind, placebo-controlled, randomized, crossover study. On the first three visits, participants consumed a beverage containing 0, 1, or 3 mg/kg caffeine (order randomized). Thirty minutes later, participants consumed a buffet breakfast, ad libitum. After leaving the laboratory, participants completed hourly appetite assessments and dietary habit books until midnight or bedtime. The fourth session consisted of questionnaires, debriefing, and compensation. MAIN OUTCOME MEASURES Total and macronutrient intake and appetite sensations in and out of the laboratory were measured. STATISTICAL ANALYSES PERFORMED Intake data were analyzed using mixed analysis of covariance (ANCOVA). Appetite sensations were analyzed using repeated measures mixed ANCOVA. RESULTS Total laboratory energy intake was lower (∼10%) after 1 mg/kg caffeine (650.4±52.2 kcal at 1 mg/kg; 721.2±63.2 at 0 mg/kg; 714.7±79.0 at 3 mg/kg) (P=0.046). In the laboratory, appetite sensations were not significantly different by caffeine treatment. Out of the laboratory, neither total intake nor appetite was significantly different by caffeine treatment. There were no significant interactions between caffeine treatment and BMI on intake and appetite sensations in or out of the laboratory. CONCLUSIONS These results suggest caffeine has weak, transient effects on energy intake and do not support caffeine as an effective appetite suppressant.

中文翻译：

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咖啡因会暂时影响早餐的食物摄入量

背景咖啡因经常被添加到膳食补充剂中，并声称它有助于减轻体重。目的 本研究的目的是检验以下假设：咖啡因给药通过降低食欲来减少实验室和自由生活的食物摄入量，并且这些影响因体重指数 (BMI) 而异。参与者/设置 50 名 18 至 50 岁的成年人完成了这项研究（42% 是男性）。排除标准包括：既往无咖啡因经历、既往摄入咖啡因后出现不良事件、服用任何药物或患有禁忌摄入咖啡因或兴奋剂或影响食欲或进食的健康状况，并报告在过去 6 个月内使用过烟草。设计和干预 参与者在四个不同的场合访问了实验室，以完成一项双盲、安慰剂对照、随机、交叉研究。在前 3 次访问中，参与者饮用了一种含有 0、1 或 3 毫克/千克咖啡因的饮料（随机顺序）。三十分钟后，参与者随意享用自助早餐。离开实验室后，参与者完成每小时的食欲评估和饮食习惯书，直到午夜或就寝时间。第四部分包括问卷调查、汇报和补偿。主要结果测量测量了实验室内外的总和常量营养素摄入量和食欲感觉。执行的统计分析 使用协方差混合分析 (ANCOVA) 分析摄入数据。使用重复测量混合 ANCOVA 分析食欲感觉。结果 摄入 1 mg/kg 咖啡因后，实验室总能量摄入量较低（~10%）（1 mg/kg 时为 650.4±52.2 kcal；0 mg/kg 时为 721.2±63.2；714.7±79。0 在 3 毫克/公斤）（P = 0.046）。在实验室中，咖啡因处理的食欲感觉没有显着差异。在实验室外，咖啡因处理的总摄入量和食欲都没有显着差异。咖啡因治疗与 BMI 对实验室内外的摄入量和食欲感觉没有显着的相互作用。结论 这些结果表明，咖啡因对能量摄入有微弱、短暂的影响，不支持咖啡因作为有效的食欲抑制剂。咖啡因治疗与 BMI 对实验室内外的摄入量和食欲感觉没有显着的相互作用。结论 这些结果表明，咖啡因对能量摄入有微弱、短暂的影响，不支持咖啡因作为有效的食欲抑制剂。在实验室内外，咖啡因治疗与 BMI 对摄入量和食欲感觉之间没有显着的相互作用。结论 这些结果表明，咖啡因对能量摄入有微弱、短暂的影响，不支持咖啡因作为有效的食欲抑制剂。