Schrauwen P, Lichtenbelt W D, Saris W H, Westerterp K R
Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands.
Am J Physiol. 1998 Jun;274(6):E1027-33. doi: 10.1152/ajpendo.1998.274.6.E1027.
In a previous study, we showed that lean subjects are capable of rapidly adjusting fat oxidation to fat intake on a high-fat (HF) diet when glycogen stores are lowered by exhaustive exercise. However, it has been proposed that obese subjects have impaired fat oxidation. We therefore studied the effect of low glycogen stores on fat oxidation after a switch from a reduced-fat (RF) diet to an HF diet in obese subjects. Ten healthy, obese male and female subjects (26 +/- 2 yr, body mass index 31.8 +/- 1.4, maximal power output 228 +/- 14 W) consumed an RF diet (30, 55, and 15% of energy from fat, carbohydrate, and protein, respectively) at home for 3 days on four occasions (days 1-3). On two occasions, subjects came to the laboratory on day 3 at 1500 to perform an exhaustive glycogen-lowering exercise test (Ex), after which they went into a respiration chamber for a 36-h stay. On the other two occasions, subjects directly entered the respiration chamber at 1800 for a 36-h stay. In the respiration chamber, they were fed, in energy balance, either an HF diet (60, 25, and 15% of energy from fat, carbohydrate, and protein, respectively) or an RF diet. All diets were consumed as breakfast, lunch, dinner, and two or more snacks per day. Twenty-four-hour respiratory quotient was 0.91 +/- 0.01, 0.89 +/- 0.01, 0.84 +/- 0.01, and 0.81 +/- 0.01 with RF diet, RF + Ex, HF, and HF + Ex treatments, respectively. With the HF treatment, fat oxidation was below fat intake, indicating the slow change of oxidation to intake on an HF diet. After the HF + Ex treatment, however, fat oxidation matched fat intake. In conclusion, obese subjects are capable of rapidly adjusting fat oxidation to fat intake when glycogen stores are lowered by exhaustive exercise.
在之前的一项研究中，我们发现，当糖原储备因力竭运动而降低时，瘦人能够在高脂（HF）饮食中迅速将脂肪氧化调节至与脂肪摄入量相匹配。然而，有人提出肥胖者的脂肪氧化存在障碍。因此，我们研究了在肥胖受试者从低脂（RF）饮食转换为HF饮食后，低糖原储备对脂肪氧化的影响。10名健康的肥胖男性和女性受试者（26±2岁，体重指数31.8±1.4，最大功率输出228±14W）在家中四次（第1 - 3天）连续3天食用RF饮食（分别提供30%、55%和15%能量的脂肪、碳水化合物和蛋白质）。其中两次，受试者在第3天15:00来到实验室进行力竭性糖原消耗运动测试（Ex），之后进入呼吸室停留36小时。另外两次，受试者于18:00直接进入呼吸室停留36小时。在呼吸室内，他们以能量平衡的方式进食HF饮食（分别提供60%、25%和15%能量的脂肪、碳水化合物和蛋白质）或RF饮食。所有饮食均作为早餐、午餐、晚餐以及每天两份或更多份零食食用。RF饮食、RF + Ex、HF和HF + Ex处理的24小时呼吸商分别为0.91±0.01、0.89±0.01、0.84±0.01和0.81±0.01。采用HF饮食处理时，脂肪氧化低于脂肪摄入量，表明在HF饮食中氧化对摄入量的变化缓慢。然而，经过HF + Ex处理后，脂肪氧化与脂肪摄入量相匹配。总之，当糖原储备因力竭运动而降低时，肥胖受试者能够迅速将脂肪氧化调节至与脂肪摄入量相匹配。
