Abstract: The impact of a ketogenic diet (KD) (<50 g/d carbohydrate, >75% fat) on athletic performance has sparked much interest and self-experimentation in the past 3–4 years. Evidence shows 3–4-week adaptations to a KD in endurance-trained athletes were associated with maintenance of moderate (46–63% VO_2max) and vigorous intensity (64–90% VO_2max) endurance exercise, while at intensities >70% VO_2max, increases in fat oxidation were associated with decreased economy (increased oxygen consumption), and in some cases, increased ratings of perceived exertion and heart rate. Two investigations in recreationally active endurance athletes noted no vigorous intensity exercise decrement following 3- and 12-week adaptations. Moderate (70–85% one repetition maximum) and near-maximal to maximal intensity (>85% 1RM) strength performance experienced no decrement following a 3-12-week KD adaptation. Beneficial effects were noted for 2000 m sprint and critical power test completed for short duration at vigorous intensity, while two additional tests noted no decrement. For sprint, near-maximal exercise (>91% VO_2max), benefit of the KD was observed for six-second sprint, while no decrement in performance was noted for two additional maximal tests. When protein is equated (grams per kilogram), one investigation noted no decrement in muscle hypertrophy, while one noted a decrement. One investigation with matched protein noted the KD group lost more body fat. In conclusion, moderate-to-vigorous intensity exercise experiences no decrement following adaptation to a KD. Decreases in exercise economy are observed >70% VO_2max in trained endurance athletes which may negate performance within field settings. Beneficial effects of the KD during short duration vigorous, and sprint bouts of exercises are often confounded by greater weight loss in the KD group. With more athletes pursuing carbohydrate-restricted diets (moderate and strict (KD)) for their proposed health benefits, more work is needed in the area to address both performance and health outcomes.

Keywords: keto-adaptation, performance, endurance, strength, high intensity, low carbohydrate




中文翻译：

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生酮饮食对运动员的影响：当前见解

摘要：在过去的3-4年中，生酮饮食（KD）（碳水化合物<50 g / d，脂肪含量> 75％）对运动成绩的影响引起了人们极大的兴趣和自我实验。证据表明，在耐力训练的运动员中适应KD的3-4周与中等强度（46–63％VO _2max）和剧烈强度（64–90％VO _2max）的耐力锻炼相关，而强度> 70％ VO _2MAX，脂肪氧化的增加与经济性下降（耗氧量增加）有关，在某些情况下，感觉到的劳累和心律评分提高。对休闲运动耐力运动员的两项调查表明，适应3周和12周后，剧烈运动强度没有降低。在进行了3-12周的KD适应后，中等强度（一次重复最高可达到70-85％）和近乎最大强度（> 85％1RM）不会降低。注意到2000 m冲刺的有益效果，并且在高强度下短时间内完成了临界功率测试，而另外两个测试未发现减量。对于短跑，近乎最大运动（> 91％VO _2max），在六秒冲刺中观察到KD的好处，而在另外两个最大测试中未发现性能下降。当蛋白质相等时（克/千克），一项研究指出肌肉肥大没有减少，而一项研究指出肌肉减少。一项与蛋白质匹配的研究表明，KD组损失了更多的体内脂肪。总之，在适应KD后，中等强度到剧烈强度的运动不会减少。观察到运动经济性降低> VO _2max大于70％在训练有素的耐力运动员中，这可能会否定田径场上的表现。在KD组中，KD在短时间内剧烈运动的有益效果和冲刺运动常常与更大的体重减轻混淆。随着越来越多的运动员追求碳水化合物限制饮食（中等和严格（KD））以实现其建议的健康益处，该领域需要开展更多工作来解决运动成绩和健康问题。

关键词：酮适应性，性能，耐力，强度，高强度，低碳水化合物