Adding fats to carbohydrate-containing meals is a common recommendation in dietetics to make meals “healthier” by reducing the glycemic response to the meal. The primary mechanism through which fat does this is by slowing the rate of gastric emptying, which leads to a slower appearance of glucose into the blood. Given that postprandial glycemia is an important risk factor for many diabetic complications, it makes complete sense to want to minimize post-meal blood glucose excursions. However, to focus solely on the blood glucose response of a meal misses the forest for the trees. There is a considerable amount of evidence to suggest that consuming starchy carbohydrates in combination with excessive dietary fat, especially saturated fat, causes an acute state of insulin resistance that may last for hours after the meal. This has been known since at least 1983, when Collier and O’Dea published research showing that adding butter to a potato...
