12/19/2025
Most people know that foods that taste sweet are generally high in sugars - small, fast digesting carbohydrates that are great fast fuels, but which can cause the release of the hormone insulin and a subsequent drop in blood sugar if you aren't engaged in exercise. You might also know that highly processed starchy foods like white bread, pasta and white rice are also digested very quickly and can cause an insulin response.
But did you know that there are some simple tricks that you can use to change the physical structure of the starch molecule and make it more resistant to digestion? By slowing down the breakdown of the starch you can change it's glycemic index and decrease the insulin response.
If you want to reduce the amount of fast digesting carbs in your diet, all you have to do is cook your rice or pasta in a large batch and refrigerate it. When you reheat it in a microwave the starch molecules stay in a more crystalline form. This is also true of cold potatoes, although if you warm them back up they become more digestible again. Bread that is stored in the fridge has a lower glycemic index than fresh bread (although you cannot beat the taste of bread right out of the oven!). And oatmeal eaten as overnight oats; soaked in milk and eaten cold has a slower digestion rate than fast-cooking oatmeal, comparable to cooked steel cut oats which are much less processed but much more expensive.
The health outcomes of increasing the amount of resistant starch in the diet are still unclear, in part because it's complicated. There are 4-5 different types of resistant starch and the formation of these compounds depends on the food you start with, the way it's prepared. People with metabolic challenges like obesity, pre-diabetes, type I and type II diabetes, heart disease and kidney disease seem to get more benefit than healthy people, and even the population of gut bacteria that you host may make a difference. But there is evidence that blood sugar and insulin levels are better, lipid profile may be improved and inflammation levels are lower, all very good things for health.
Whole unprocessed foods (a fresh apple rather than apple juice) will always require more digestion to break down the cell structure of the food, but knowing that cooling moist cooked starches and either reheating in a microwave or consuming them cold can have a big impact on maintaining a stable blood glucose is powerful.