Swinburn B A
Department of Community Health, University of Auckland, New Zealand.
Ann N Y Acad Sci. 1993 Jun 14;683:102-9. doi: 10.1111/j.1749-6632.1993.tb35697.x.
Evidence from the best studies available in the literature suggest that the isocaloric substitution of dietary fat for dietary carbohydrate does not cause insulin resistance. Although many studies show several differences between the diets (for example, changes in dietary fiber or fat subtype), the diets were primarily designed to compare the effects of the fat/carbohydrate content, and a true important effect of dietary fat on insulin action should have been detected. Some studies found other changes in carbohydrate metabolism such as improvements in insulin secretion and glucose effectiveness (Sg) that could contribute to the conflicting results. For example, glucose uptake as measured by the euglycemic clamp includes both insulin-dependent and non-insulin-dependent (SG) factors, so that the M value could be affected by changes in SG as well as in insulin action. All of these studies have used isocaloric substitution so that body weight is maintained. This constraint, while important for determining and direct effect of dietary fat, may lead to false conclusions about its overall effects on insulin action. One of the most common and potent causes of insulin resistance is obesity, and dietary fat is of singular importance in the genesis of obesity. Inasmuch as an ad libitum reduced fat diet causes weight loss, the overall effect of dietary fat reduction may be an improvement in insulin action because of weight loss even in the absence of any direct effects. Long-term studies of the effects of fat content within ad libitum diets are needed to place these largely negative results from isocaloric studies in context.
文献中现有最佳研究的证据表明，用膳食脂肪等量替代膳食碳水化合物不会导致胰岛素抵抗。尽管许多研究显示了这些饮食之间的若干差异（例如，膳食纤维或脂肪亚型的变化），但这些饮食主要是为了比较脂肪/碳水化合物含量的影响，而膳食脂肪对胰岛素作用的真正重要影响应该已经被检测到了。一些研究发现碳水化合物代谢的其他变化，如胰岛素分泌和葡萄糖效能（Sg）的改善，这可能导致了相互矛盾的结果。例如，用正常血糖钳夹法测量的葡萄糖摄取包括胰岛素依赖性和非胰岛素依赖性（SG）因素，因此M值可能受到SG变化以及胰岛素作用变化的影响。所有这些研究都采用了等量替代，以使体重维持不变。这种限制虽然对于确定膳食脂肪的直接影响很重要，但可能会导致关于其对胰岛素作用的总体影响的错误结论。胰岛素抵抗最常见和最主要的原因之一是肥胖，而膳食脂肪在肥胖的发生中具有独特的重要性。由于随意减少脂肪的饮食会导致体重减轻，即使没有任何直接影响，减少膳食脂肪的总体效果可能是由于体重减轻而使胰岛素作用得到改善。需要对随意饮食中脂肪含量的影响进行长期研究，以便将这些来自等量研究的主要负面结果置于适当的背景中。
