Low-fat diet alters intramuscular substrates and reduces lipolysis and fat oxidation during exercise
Low-fat diet alters intramuscular substrates and reduces lipolysis and fat oxidation during exercise
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DOI：
10.1152/ajpendo.2001.280.3.e391
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发表时间：
2001-03-01
影响因子：
5.1
通讯作者：
Zderic, TW
中科院分区：
文献类型：
--
作者：
Coyle, EF;Jeukendrup, AE;Zderic, TW
我们确定低脂饮食是否会降低运动期间肌内甘油三酯 (IMTG) 浓度、全身脂肪分解、总脂肪氧化以及计算的非血浆脂肪酸 (FA) 氧化。对 7 名经过耐力训练的自行车运动员进行了为期 3 周的研究，在此期间，他们每天锻炼 2 小时，最大 O-2 摄入量 (V) 超过点 O-2max 的 70%，消耗量约为 4,400 kcal/天。在第一周，他们摄入的脂肪提供了 32% 的能量。在第 2 周和第 3 周，他们被随机分配吃 2% 或 22% 的脂肪能量（2% FAT 或 22% FAT）。与22% FAT相比，2% FAT降低了静息状态下IMTG浓度并升高了肌糖原浓度（P<0.05）。研究了 1 小时运动期间的代谢情况，运动强度比禁食状态下进行的 dotO(2max) 提高了 67% (V)。与 22% FAT 相比，2% FAT 导致总脂肪氧化减少 27%（P<0.05），而不会改变稳定同位素测定的血浆游离脂肪酸或葡萄糖消失率。因此，与 22% FAT 相比，2% FAT 使计算的非血浆 FA 氧化减少 40%，全身脂肪分解减少 19%，同时增加计算的最小肌糖原氧化（所有 P<0.05）。总之，极低脂肪（能量的 2%）和高碳水化合物饮食可降低空腹状态运动期间的全身脂肪分解、总脂肪氧化和非血浆 FA 氧化，并降低肌内甘油三酯浓度。
We determined whether a low-fat diet reduces intramuscular triglyceride (IMTG) concentration, whole body lipolyis, total fat oxidation, and calculated nonplasma fatty acid (FA) oxidation during exercise. Seven endurance-trained cyclists were studied over a 3-wk period during which time they exercised 2 h/day at 70% of maximum O-2 uptake (V) over dot O-2max and consumed similar to4,400 kcal/day. During the 1st wk, their fat intake provided 32% of energy. During the 2nd and 3rd wk, they were randomly assigned to eat 2 or 22% of energy from fat (2% FAT or 22% FAT). Compared with 22% FAT, 2% FAT lowered IMTG concentration and raised muscle glycogen concentration at rest (P< 0.05). Metabolism was studied during 1 h of exercise at 67% (V) over dotO(2max) performed in the fasted state. 2% FAT resulted in a 27% reduction (P< 0.05) in total fat oxidation vs. 22% FAT without altering the stable isotopically determined rates of plasma free fatty acid or glucose disappearance. Therefore, 2% FAT reduced calculated nonplasma FA oxidation by 40% in association with a 19% reduction in whole body lipolysis while increasing calculated minimal muscle glycogen oxidation compared with 22% FAT (all P< 0.05). In summary, an extremely low fat (2% of energy) and high-carbohydrate diet lowers whole body lipolysis, total fat oxidation, and nonplasma FA oxidation during exercise in the fasted state in association with a reduced concentration of intramuscular triglyceride.