Is reheated food better for blood sugar?

Eating pasta, rice and potatoes as leftovers can have a positive effect on blood sugar levels. So is reheated food really healthier?

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 level to rise. Perhaps you yourself have already observed such a rise in blood sugar.

Why is it better to reheat the same foods?

When we cook these carbohydrates and then let them cool, the resistant starch in the food increases. Resistant starch is a type of dietary fiber that is resistant to digestion. It is fermented rather than digested in the small intestine.

A high proportion of resistant starch in the diet has a positive effect on blood sugar levels, as it is not converted into sugar as quickly.

The good thing is that the resistant starch remains elevated even when you reheat the food. In other words, when reheated, these pre-cooked foods have a higher fiber content, which leads to a weaker rise in blood sugar. So yes, reheated foods are better for us and our blood sugar response.

The "reheated food" experiment

In the picture above you can see an experiment we did as a team. With the fresh pasta, you can clearly see that the overall blood sugar level was higher and it took longer for the blood sugar level to return to baseline. This means that the body has to work hard to balance the blood sugar curve.

In brief

This means that we can transform high-carbohydrate meals into healthier, higher-fiber meals without changing a single ingredient. The only thing we need to do is be patient, let the food cool down and reheat it. This is how pasta salad or the pasta from the day before becomes a great, healthier lunch at the office. What will your blood sugar levels look like when you eat that 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 what our glucose curve looks like - the composition and ingredients of meals, your exercise, your sleep, your cycle phase, your hormone levels, and much more. The best way to find out what works for you is to experiment and try it out for 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.