Background Thermogenic fitness drink formulas (TFD) have been shown to increase energy expenditure and markers of lipid metabolism. The purpose of the current study was to compare TFD formulas containing different caffeine concentrations versus a placebo drink on energy expenditure and lipid metabolism at rest and during exercise. Methods Thirty-two recreationally active participants (22.9 ± 0.7 y, 167.1 ± 1.4 cm, 68.8 ± 2.0 kg, 24.0 ± 1.2% fat) who were regular caffeine consumers, participated in this randomized, double-blind, crossover design study. Participants reported to the laboratory on three occasions, each of which required consumption of either a TFD containing 140 mg or 100 mg of caffeine or a placebo. Baseline measurements of resting energy expenditure (REE) and resting fat oxidation (RFO) were assessed using indirect calorimetry as well as measurements of serum glycerol concentration. Measurements were repeated at 30, 60, 90 min post-ingestion. Following resting measures, participants completed a graded exercise test to determine maximal oxygen uptake (V̇O 2max ), maximal fat oxidation (MFO) and the exercise intensity that elicits MFO (Fat max ), and total energy expenditure (EE). Results A significant interaction was shown for REE ( p < 0.01) and RFO ( p < 0.01). Area under the curve analysis showed an increased REE for the 140 mg compared to the 100 mg formula ( p = 0.02) and placebo ( p < 0.01) and an increased REE for the 100 mg formula compared to placebo ( p = 0.02). RFO significantly decreased for caffeinated formulas at 30 min post ingestion compared to placebo and baseline ( p < 0.01) and significantly increased for the 140 mg formula at 60 min post-ingestion ( p = 0.03). A main effect was shown for serum glycerol concentrations over time ( p < 0.01). No significant differences were shown for V̇O 2max ( p = 0.12), Fat max ( p = 0.22), and MFO ( p = 0.05), and EE ( p = 0.08) across drinks. Conclusions Our results suggest that TFD formulas containing 100 and 140 mg of caffeine are effective in increasing REE and that a 40 mg of caffeine difference between the tested formulas may impact REE and RFO in healthy individuals within 60 min of ingestion.

中文翻译：

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含 140 毫克和 100 毫克咖啡因的产热健身饮料配方对休息和运动时的能量消耗和脂肪代谢的急性影响

背景 生热健身饮料配方 (TFD) 已被证明可以增加能量消耗和脂质代谢标志物。当前研究的目的是比较含有不同咖啡因浓度的 TFD 配方与安慰剂饮料在休息和运动期间的能量消耗和脂质代谢。方法 32 名经常饮用咖啡因的休闲活跃参与者（22.9 ± 0.7 岁，167.1 ± 1.4 cm，68.8 ± 2.0 kg，24.0 ± 1.2% 脂肪）参与了这项随机、双盲、交叉设计研究。参与者向实验室报告了三次，每次都需要消耗含有 140 毫克或 100 毫克咖啡因的 TFD 或安慰剂。使用间接量热法以及血清甘油浓度的测量来评估静息能量消耗 (REE) 和静息脂肪氧化 (RFO) 的基线测量值。在摄入后 30、60、90 分钟重复测量。休息后，参与者完成了分级运动测试，以确定最大摄氧量 (V̇O 2max )、最大脂肪氧化 (MFO) 和引起 MFO 的运动强度 (Fat max ) 和总能量消耗 (EE)。结果 REE ( p < 0.01) 和 RFO ( p < 0.01) 显示出显着的相互作用。曲线下面积分析显示，与 100 mg 配方 (p = 0.02) 和安慰剂 (p < 0.01) 相比，140 mg 的 REE 增加，与安慰剂 (p = 0.02) 相比，100 mg 配方的 REE 增加。与安慰剂和基线相比，摄入后 30 分钟含咖啡因配方的 RFO 显着降低 (p < 0.01)，摄入 60 分钟后 140 毫克配方的 RFO 显着增加 (p = 0.03)。随着时间的推移，血清甘油浓度显示出主要影响（p < 0.01）。不同饮料的 V̇O 2max (p = 0.12)、Fat max (p = 0.22) 和 MFO (p = 0.05) 以及 EE (p = 0.08) 没有显着差异。结论 我们的结果表明，含有 100 和 140 毫克咖啡因的 TFD 配方可有效增加 REE，并且测试配方之间 40 毫克的咖啡因差异可能会影响健康个体摄入 60 分钟内的 REE 和 RFO。随着时间的推移，血清甘油浓度显示出主要影响（p < 0.01）。不同饮料的 V̇O 2max (p = 0.12)、Fat max (p = 0.22) 和 MFO (p = 0.05) 以及 EE (p = 0.08) 没有显着差异。结论 我们的结果表明，含有 100 和 140 毫克咖啡因的 TFD 配方可有效增加 REE，并且测试配方之间 40 毫克的咖啡因差异可能会影响健康个体摄入 60 分钟内的 REE 和 RFO。随着时间的推移，血清甘油浓度显示出主要影响（p < 0.01）。不同饮料的 V̇O 2max (p = 0.12)、Fat max (p = 0.22) 和 MFO (p = 0.05) 以及 EE (p = 0.08) 没有显着差异。结论 我们的结果表明，含有 100 和 140 毫克咖啡因的 TFD 配方可有效增加 REE，并且测试配方之间 40 毫克的咖啡因差异可能会影响健康个体摄入 60 分钟内的 REE 和 RFO。