When we eat carbohydrates such as rice, pasta or potatoes, they are broken down in the intestines and absorbed as sugar. This causes our blood sugar levels to rise. You might have observed such a glucose spike yourself already. So this is nothing new.

But when we eat pasta, rice and potatoes as leftovers, our blood sugar levels don’t rise that quickly. #fascinating

When we cook these carbohydrates and then cool them, the resistant starch in the food increases. Resistant starch is a type of dietary fiber that is, as the name suggests, resistant to digestion. It is fermented rather than digested in the small intestine. This small difference has a positive effect on our blood sugar, because the carb-to-sugar transformation takes longer.

The good thing is that the resistant starch remains elevated even when you reheat the food, which means that it has a higher fiber content. And fiber is good for balanced blood sugar.
In other words, when reheated foods high in starch lead to a smaller increase in blood sugar levels. So yes, reheated food is better for us and our blood glucose response.

In the image above shows an experiment we did with the team.
With the fresh pasta (top curve), you can clearly see that the glucose levels were higher overall, and it took longer for the glucose levels to reach the starting blood sugar level again. This means that the body works hard to balance your blood sugar curve, ideally, you want to reach your baseline levels latest within 2.5 hours.

This means that without changing a single ingredient we can transform our beloved meals that are rich in starches into healthier, more blood sugar-friendly meals.
The only thing we need to do is be patient, let the food cool completely and reheat it.
This is how pasta salad becomes a great office lunch.

What will your blood sugar levels look like when you eat the lasagna you still have in the freezer?

And remember: we are all unique and so is our response to food and meals. It depends on many factors how our glucose curve looks like – your meal composition and ingredients, your movement, your sleep, your cycle phase, hormonal levels and much more. The best way to find out what works for you is to experiment and try it out yourself.

Source: Hodges C, Archer F, Chowdhury M, Evans BL, Ghelani DJ, Mortoglou M, Guppy FM. Method of Food Preparation Influences Blood Glucose Response to a High-Carbohydrate Meal: A Randomised Cross-over Trial. Foods. 2019 Dec 25;9(1):23. doi: 10.3390/foods9010023. PMID: 31881647; PMCID: PMC7022949.