Human Performance Laboratory, The College of New Jersey, Ewing, New Jersey, USA.
J Am Coll Nutr. 2020 Sep-Oct;39(7):665-675. doi: 10.1080/07315724.2020.1725686. Epub 2020 Feb 10.
Ketogenic diets (KDs) have received increasing attention among athletes and physically active individuals. However, the question as to whether and how the diet could benefit this healthy cohort remains unclear. This study was designed to systematically review the existing evidence concerning the effect of KDs on body composition, aerobic and anaerobic capacity, muscle development, and sports performance in normal-weight individuals including athletes. A systematic search of English literature was conducted through electronic databases including PubMed, EBSCOhost, and Google Scholar. Upon the use of search criteria, 23 full-text original human studies involving non-obese participants were included in this review. For more stratified and focused analysis, these articles were further categorized based on the outcomes being examined including 1) body mass (BM) and %fat, 2) substrate utilization, 3) blood substrate and hormonal responses, 4) aerobic capacity and endurance performance, and 5) strength, power, and anaerobic capacity. Our review indicates that a non-calorie-restricted KD carried out for ≥3 weeks can produce a modest reduction in BM and %fat, while maintaining fat-free mass. This diet leads to augmented use of fat as fuel, but this adaptation doesn't seem to improve endurance performance. Additionally, KDs combined with resistance training will pose no harm to developing strength and power, especially when protein intake is increased modestly. It appears that a non-calorie-restricted KD provides minimal ergogenic benefits in normal-weight individuals including athletes, but can be used for optimizing BM and body composition without compromising aerobic and anaerobic performance. Key teaching pointsKetogenic diets have received increasing attention among athletes and physically active individuals.It remains elusive as to whether ketogenic diets could confer ergogenic benefits for those who are normal weight but want to use the diet to improve fitness and performance.An interesting dilemma exists in that ketogenic diets can reduce body mass and %fat and increase fat oxidation, but they can also decrease glycogen stores and limit sports performance.This review concludes that a non-calorie-restricted ketogenic diet provides minimal ergogenic benefits in normal-weight individuals, but can be used to optimize body mass and composition without compromising athletic performance.This finding can be important for esthetic or weight-sensitive athletes because the diet may allow them to reach a target body mass without having to sacrifice athletic performance.The ketogenic diet-induced metabolic adaptations require a state of ketosis, and thus caution should be taken because an excessive increase in ketone bodies can be detrimental to health.
生酮饮食（KDs）在运动员和活跃人群中受到越来越多的关注。然而，关于这种饮食是否以及如何使这一健康人群受益的问题仍然不清楚。本研究旨在系统地回顾现有的关于生酮饮食对正常体重个体（包括运动员）的身体成分、有氧和无氧能力、肌肉发育和运动表现的影响的证据。通过电子数据库（包括 PubMed、EBSCOhost 和 Google Scholar）进行了英语文献的系统搜索。在使用搜索标准后，共有 23 项涉及非肥胖参与者的全文原始人体研究被纳入本综述。为了进行更具针对性和重点的分析，根据所检查的结果进一步对这些文章进行了分类，包括 1）体重（BM）和体脂%，2）底物利用，3）血液底物和激素反应，4）有氧能力和耐力表现，以及 5）力量、功率和无氧能力。我们的综述表明，进行非热量限制的生酮饮食≥3 周可以适度减少 BM 和体脂%，同时保持无脂肪质量。这种饮食导致脂肪作为燃料的使用增加，但这种适应似乎不会提高耐力表现。此外，生酮饮食与阻力训练相结合不会对力量和功率的发展造成伤害，尤其是当适度增加蛋白质摄入时。看来，非热量限制的生酮饮食对正常体重的个体（包括运动员）提供的有益效果微乎其微，但可以用于优化 BM 和身体成分，而不会影响有氧和无氧表现。主要教学要点生酮饮食在运动员和活跃人群中越来越受到关注。对于那些体重正常但希望通过饮食来提高健康水平和表现的人来说，生酮饮食是否能带来有益的效果仍然难以确定。一个有趣的困境是，生酮饮食可以减轻体重和体脂%，增加脂肪氧化，但也会减少糖原储存并限制运动表现。本综述得出的结论是，非热量限制的生酮饮食对正常体重个体提供的有益效果微乎其微，但可以用于优化体重和身体成分，而不会影响运动表现。对于注重美观或体重的运动员来说，这一发现可能很重要，因为这种饮食可以让他们达到目标体重，而不必牺牲运动表现。生酮饮食引起的代谢适应需要酮症状态，因此应该谨慎，因为酮体的过度增加可能对健康有害。
