Are carbohydrates like sweet potato and rice actually more absorbable in the body when they are warm as opposed to out of the fridge? When they're out of the fridge, are they more like resistant starch? As in, less carbohydrate is absorbed by the body and more just moves through the digestive tract.

Carbohydrates such as sweet potatoes and rice can indeed exhibit changes in how they are absorbed and metabolized based on temperature. Cooking these foods and then refrigerating them promotes the formation of resistant starch, a type of starch that resists digestion in the small intestine, akin to fiber. This process modifies the molecular structure of the starch, potentially lowering the glycemic response when the food is consumed cold or reheated.

For instance, cooling cooked carbohydrates like potatoes or rice can lead to a lower glucose spike compared to consuming them warm. One study found that the glucose spike was reduced by about 11 points after cooling, compared to when the starchy foods were consumed hot and fresh. This cooling process was shown to increase resistant starch content, reducing the amount of carbohydrate absorbed by the body and resulting in these foods behaving more like fiber 1.

Moreover, reheating the cooled food does not seem to reverse this change. The resistant starch remains, which means even reheated, the food would generally cause a smaller glucose spike compared to its freshly cooked version 2 3. This method is a useful strategy for those managing metabolic health or looking to mitigate the impact of high-glycemic foods.