Lewis S B, Wallin J D, Kane J P, Gerich J E
Am J Clin Nutr. 1977 Feb;30(2):160-70. doi: 10.1093/ajcn/30.2.160.
The metabolic consequences of two hypocaloric diets were assessed in 10 obese men. The study, performed on a metabolic ward, compared the response of these men to two cholesterol-free liquid formula diets of differing composition (10 kcal/kg per day, 70% carbohydrate, 20% protein, 10% fat versus 70% fat, 20% protein, 10% carbohydrate) but identical in calories. These were administered for 14 days in a random order and each diet was preceded by a 7-day control weight maintenance diet (30 kcal/kg per day, 40% carbohydrate, 20% protein, 40% fat). The low calorie diets were well tolerated by the men and effected similar losses of nonaqueous body weight. Fasting glucose and insulin decreased significantly in these men after they ingested either weight loss diet for 14 days, but the change in each parameter was greater for high fat as compared to high carbohydrate (15% versus 7% and 67% versus 35%, respectively, P less than 0.01). In contrast, fasting glucagon concentration decreased in these subjects to a greater extent in response to the high carbohydrate diet (35% versus 16%, P less than 0.01). This adaptive response thus resulted in a 50% fall in insulin:glucagon molar ratio for high fat and no change for high carbohydrate weight loss. Despite these hormonal alterations no change in glucose tolerance was observed. Fasting serum triglyceride and cholesterol levels declined in these subjects to a greater extent following the high fat compared to the high carbohydrate regimen (45% versus 28%, P less than 0.01 and 8% versus 3%, not significant, respectively). These changes reflected decrements in very low density lipoproteins alone. Despite similar increments in free fatty acid levels, (350% versus 270%, not significant) serum ketone body (beta-hydroxybutyrate and acetoacetate) concentrations increased 7-fold on the high fat diet compared to the high carbohydrate diet, P less than 0.001. The hyperketonemia of these men in response to the high fat, low calorie diet suggested the occurrence of a shift in hepatic free fatty acid metabolism toward ketogenesis rather than triglyceride synthesis. The associated decrease in the insulin: glucagon molar ratio raised the question of a possible role for these hormones in the adaptation.
在10名肥胖男性中评估了两种低热量饮食的代谢后果。该研究在代谢病房进行，比较了这些男性对两种成分不同（每天10千卡/千克，70%碳水化合物、20%蛋白质、10%脂肪与70%脂肪、20%蛋白质、10%碳水化合物）但热量相同的无胆固醇液体配方饮食的反应。这些饮食以随机顺序给予14天，每种饮食之前都有一个为期7天的维持体重对照饮食（每天30千卡/千克，40%碳水化合物、20%蛋白质、40%脂肪）。这些男性对低热量饮食耐受性良好，且非水体重减轻相似。在摄入任何一种减肥饮食14天后，这些男性的空腹血糖和胰岛素显著下降，但与高碳水化合物饮食相比，高脂肪饮食时每个参数的变化更大（分别为15%对7%和67%对35%，P<0.01）。相反，空腹胰高血糖素浓度在这些受试者中对高碳水化合物饮食的反应下降幅度更大（35%对16%，P<0.01）。这种适应性反应导致高脂肪饮食时胰岛素：胰高血糖素摩尔比下降50%，而高碳水化合物减肥饮食时无变化。尽管有这些激素改变，但未观察到葡萄糖耐量的变化。与高碳水化合物饮食方案相比，高脂肪饮食后这些受试者的空腹血清甘油三酯和胆固醇水平下降幅度更大（分别为45%对28%，P<0.01和8%对3%，无显著性差异）。这些变化仅反映了极低密度脂蛋白的减少。尽管游离脂肪酸水平有相似的升高（350%对270%，无显著性差异），但与高碳水化合物饮食相比，高脂肪饮食时血清酮体（β-羟基丁酸和乙酰乙酸）浓度增加了7倍，P<0.001。这些男性对高脂肪、低热量饮食的高酮血症表明肝脏游离脂肪酸代谢向生酮作用而非甘油三酯合成发生了转变。胰岛素：胰高血糖素摩尔比的相关下降引发了这些激素在这种适应性变化中可能作用的问题。
