Because of our jobs, people come to us all the time asking for advice for their health. We always share what information we have with them. Of course, like on the blog, we tell them to talk to their doctor about their health concerns. But, sometimes, they ask us for advice about things that could be considered dietary urban legends.
Someone asked their friend who works on our team if it’s true that making potatoes cold lowers their carb content. The answer isn’t quite as simple as a yes or no.
On the one hand, cooling down food won’t make carbs disappear. They are still there. However, cooling them after cooking can convert some carbs into resistant starches. Resistant starches are harder for your body to absorb, so they don’t impact your blood sugar as much. But there are still more “howevers” in this story.
In a study in 1992, scientists found that boiled potatoes chilled overnight have 2.8 times more resistant starch. But chewing lowers the amount of resistance starch in the food. Studies in 2021 came to two different conclusions. One found that foods rich in resistant starches made people more full but didn’t help blood sugar. The other concluded that there was no strong evidence that chilling foods impacted carbohydrate digestibility in real-world settings.
There is some good news, those studies didn’t use people with blood sugar concerns. It’s hard to conclude how it impacts blood spikes for people concerned about their blood sugar health when it hasn’t been studied in them. In 2022, a study gave people with blood sugar concerns white rice. Either the rice was freshly prepared, or it had been chilled for 24 hours and reheated. The people eating reheated rice had significantly lower blood sugar after eating than those eating fresh rice.
The method of cooking a potato can dramatically change its GI. Fries have a GI of 95, while a serving of boiled potatoes that have been cooled and reheated has a GI of 50.
Additionally, Dr. Steven Masley points out that most of the fiber in a potato is in the skin. So he recommends eating small, cooled boiled potatoes that are still in their jacket as they will have the highest skin-to-flesh ratio. He also recommends protein and healthy fats to further reduce how they impact blood sugar.
As mentioned before, rice developed resistant starch when cooled. So do pasta, barley, beans, lentils and peas. We’re always extolling the virtues of beans and lentils. Cooling and rewarming them may make them even more helpful to your health.
Everyone’s blood sugar levels react differently to different foods. We hear from people all the time that some foods impact them more than other people. This trick may help you enjoy potatoes more frequently, but cooling potatoes doesn’t actually lower their carbs; it just makes them less available to your boy. You may want to experiment with it, but first, discuss it with your doctor and ensure they could be a healthy part of your diet.