Horvath P J, Eagen C K, Fisher N M, Leddy J J, Pendergast D R
Department of Physical Therapy, University at Buffalo, New York 14214, USA.
J Am Coll Nutr. 2000 Feb;19(1):52-60. doi: 10.1080/07315724.2000.10718914.
Low dietary fat intake has become the diet of choice for many athletes. Recent studies in animals and humans suggest that a high fat diet may increase VO2max and endurance. We studied the effects of a low, medium and high fat diet on performance and metabolism in runners.
Twelve male and 13 female runners (42 miles/week) ate diets of 16% and 31% fat for four weeks. Six males and six females increased their fat intakes to 44%. All diets were designed to be isocaloric. Endurance and VO2max were tested at the end of each diet. Plasma levels of lactate, pyruvate, glucose, glycerol, and triglycerides were measured before and after the VO2max and endurance runs. Free fatty acids were measured during the VO2max and endurance runs.
Runners on the low fat diet ate 19% fewer calories than on the medium or high fat diets. Body weight, percent body fat (males=71 kg and 16%; females=57 kg and 19%), VO2max and anaerobic power were not affected by the level of dietary fat. Endurance time increased from the low fat to medium fat diet by 14%. No differences were seen in plasma lactate, glucose, glycerol, triglycerides and fatty acids when comparing the low versus the medium fat diet. Subjects who increased dietary fat to 44% had higher plasma pyruvate (46%) and lower lactate levels (39%) after the endurance run.
These results suggest that runners on a low fat diet consume fewer calories and have reduced endurance performance than on a medium or high fat diet. A high fat diet, providing sufficient total calories, does not compromise anaerobic power.
低脂肪饮食已成为许多运动员的首选饮食方式。近期对动物和人类的研究表明，高脂肪饮食可能会提高最大摄氧量（VO2max）和耐力。我们研究了低、中、高脂肪饮食对跑步者运动表现和新陈代谢的影响。
12名男性和13名女性跑步者（每周跑42英里）食用脂肪含量分别为16%和31%的饮食，为期四周。6名男性和6名女性将脂肪摄入量提高到44%。所有饮食的热量均设计为相等。在每种饮食结束时测试耐力和最大摄氧量。在最大摄氧量和耐力跑前后测量血浆中乳酸、丙酮酸、葡萄糖、甘油和甘油三酯的水平。在最大摄氧量和耐力跑期间测量游离脂肪酸。
食用低脂肪饮食的跑步者摄入的热量比食用中脂肪或高脂肪饮食时少19%。体重、体脂百分比（男性=71千克，16%；女性=57千克，19%）、最大摄氧量和无氧功率不受饮食脂肪水平的影响。耐力时间从低脂肪饮食到中脂肪饮食增加了14%。比较低脂肪饮食和中脂肪饮食时，血浆乳酸、葡萄糖、甘油、甘油三酯和脂肪酸没有差异。将饮食脂肪增加到44%的受试者在耐力跑后血浆丙酮酸水平较高（46%），乳酸水平较低（39%）。
这些结果表明，与中脂肪或高脂肪饮食相比，低脂肪饮食的跑步者摄入的热量更少，耐力表现更低。提供足够总热量的高脂肪饮食不会损害无氧功率。
