Speechly D P, Buffenstein R
Department of Physiology, University of the Witwatersrand Medical School, 7 York Road, Parktown, 2193, Johannesburg, South Africa.
Eur J Clin Nutr. 2000 Mar;54(3):225-33. doi: 10.1038/sj.ejcn.1600924.
To test the hypothesis that caloric and fat intake in a pre-load meal have no subsequent effects upon blood glucose and insulin concentrations, perceived hunger, subsequent food intake and appetite control in lean and obese men.
Lean and obese men reported to the laboratory in the morning in a fasted state where they were subject to an eating test based on the pre-load-test meal paradigm, using a double-blind protocol. The breakfast pre-load was either a reduced caloric low-fat (LF) meal or an overfeeding high-fat (HF) meal. LF was 20% of each individual's average daily energy requirement (ADER) and comprised 60% carbohydrate, 27% protein, and 13% fat, whilst HF was adjusted to yield 55% of the ADER, and comprised 45% carbohydrate, 22% protein and 43% fat. The pre-loads on both trials were administered as one single mean, and were given in a random order. After 5(1/2) h, an ad libitum test-lunch was given to determine how much energy was consumed. Between the two meals, blood samples were collected and subjective hunger ratings were assessed hourly. These variables were measured at 30-min intervals for 75 min after the ad libitum meal.
Twelve healthy men, six of whom were lean (BMI 22. 50+/-1.08 kg.m2) and six of whom were obese (BMI 39.05+/-11.63 kg. m2) were recruited.
When given 55% of their ADER in a HF pre-load meal, the obese group consumed more energy (5426+/-1126 kJ; F1,20=11.45, P<0.01), than the lean group did (3473+/-1114 kJ), accounting for 45% of the ADER in that meal setting. However, no differences between lean and obese intake were noted at the test meal following a LF pre-load. The lean group exhibited a significant inverse correlation (r=0.628, P<0.05) between serum insulin concentration before eating the test meal and the amount of energy consumed at the test meal, while such a relationship was absent in the obese group.
The obese males were unable to compensate for the caloric overloading when fed a HF (55% ADER) pre-load at a subsequent test meal, whereas a calorically reduced pre-load (20% ADER) produced similar intakes to the lean control group. The inverse relationship noted in the lean group between insulin levels before the test meal and the energy intake at that test meal suggests that insulin may play a role in the regulation of appetite - satiety mechanism in lean males. The absence of such a relationship in the obese may suggest the site for possible appetite dysfunction contributing to obesity. These results further suggest that when obese individuals consume a high-fat meal they are prone to passive overconsumption, whereas lean study participants appear to be more resistant to such a phenomenon.
验证如下假设：预负荷餐中的热量和脂肪摄入量对瘦人和肥胖男性的血糖和胰岛素浓度、主观饥饿感、随后的食物摄入量及食欲控制无后续影响。
瘦人和肥胖男性于上午空腹状态下到实验室报到，在此进行基于预负荷 - 测试餐范式的进食测试，采用双盲方案。早餐预负荷餐要么是低热量低脂（LF）餐，要么是高热量高脂（HF）餐。LF餐为每人平均每日能量需求（ADER）的20%，由60%的碳水化合物、27%的蛋白质和13%的脂肪组成，而HF餐经调整后提供55%的ADER，由45%的碳水化合物、22%的蛋白质和43%的脂肪组成。两次试验中的预负荷餐均作为单一餐量一次性给予，且随机安排顺序。5个半小时后，提供一顿随意的测试午餐，以确定摄入的能量。两餐之间，每小时采集血样并评估主观饥饿评分。在随意进食餐后75分钟内，每隔30分钟测量这些变量。
招募了12名健康男性，其中6名瘦人（BMI 22.50±1.08 kg·m²），6名肥胖者（BMI 39.05±11.63 kg·m²）。
当肥胖组在HF预负荷餐中摄入55%的ADER时，其消耗的能量（5426±1126 kJ；F1,20 = 11.45，P<0.01）比瘦组（3473±1114 kJ）多，占该餐量设置下ADER的45%。然而，在LF预负荷后的测试餐中，未发现瘦组和肥胖组的摄入量有差异。瘦组在食用测试餐之前的血清胰岛素浓度与测试餐中消耗的能量之间呈现显著负相关（r = 0.628，P<0.05），而肥胖组不存在这种关系。
肥胖男性在随后的测试餐中食用HF（55% ADER）预负荷餐时，无法补偿热量过载情况，而热量减少的预负荷餐（20% ADER）产生的摄入量与瘦对照组相似。瘦组中测试餐之前的胰岛素水平与该测试餐中的能量摄入量之间的负相关关系表明，胰岛素可能在瘦男性的食欲 - 饱腹感调节机制中发挥作用。肥胖者中不存在这种关系可能表明存在导致肥胖的潜在食欲功能障碍部位。这些结果进一步表明，肥胖个体食用高脂肪餐时容易被动过度进食，而瘦的研究参与者似乎对这种现象更具抵抗力。
