The Surprising Health Power of Leftover Potatoes
Don’t toss those leftovers!
Why Cooling and Reheating Your Spuds May Be Better Than Eating Them Hot
When you think of health foods, potatoes probably don’t top your list. Long maligned as a “white carb” that spikes blood sugar, the humble potato is often overlooked in wellness conversations.
But what if I told you that leftover potatoes—yes, those cold or reheated ones—may actually be better for your blood sugar and gut health than fresh-off-the-stove spuds?
The secret lies in something called resistant starch—a unique form of carbohydrate that behaves more like fiber than sugar in your body.
What Is Resistant Starch?
Resistant starch is a type of starch that resists digestion in the small intestine. Instead of being broken down into glucose, it travels to the large intestine, where it acts as a prebiotic fiber, feeding beneficial gut bacteria.
Types of resistant starch include:
RS1 – Found in whole grains and seeds
RS2 – Found in raw potatoes and green bananas
RS3 – Formed when starchy foods like potatoes, rice, or pasta are cooked and then cooled
✔️ That’s right: RS3 is created when you cook and chill your potatoes. The process is called retrogradation, and it increases the amount of resistant starch in the food.
Benefits of Resistant Starch in Leftover Potatoes
1. Improved Blood Sugar Control
Eating cooled or reheated potatoes leads to a lower glycemic response compared to hot, freshly cooked ones. That means your blood sugar rises more slowly, which is especially important for people managing insulin resistance or prediabetes.
Study: A 2019 study in Nutrients found that retrograded resistant starch reduces postprandial glucose and insulin levels.
2. Supports Gut Health
Resistant starch acts as prebiotic fuel for your microbiome, promoting the growth of beneficial bacteria like Bifidobacteria and Akkermansia. These bacteria ferment resistant starch into short-chain fatty acids (SCFAs) like butyrate, which:
Reduce inflammation
Support immune function
Strengthen the gut lining
3. Increases Satiety
Because it slows digestion, resistant starch keeps you full longer—reducing cravings and helping with appetite regulation.
4. May Improve Metabolic Health
Some studies suggest resistant starch can improve insulin sensitivity and reduce abdominal fat over time when consumed regularly as part of a balanced diet.
Does Reheating Destroy the Benefits?
Nope. In fact, reheating cooled potatoes does not reverse the formation of resistant starch. You’ll still get the benefits—even if you sauté or microwave them the next day. The key is that they’ve been cooled long enough for the starch structure to change.
Tips for Enjoying Leftover Potatoes the Smart Way
Chill for at least 4 hours, preferably overnight.
Use olive oil, herbs, or vinegar when reheating for even more metabolic perks.
Try them in potato salad, frittatas, or roasted with turmeric (hello, anti-inflammatory combo!).
Keep the skin on for extra fiber and antioxidants.
Easy Recipe: Gut-Loving Leftover Potato Bowl
1 cup cooked, cooled diced potatoes
1 tbsp olive oil
1 cup baby spinach
1 boiled egg or tofu
1 tbsp apple cider vinegar
Sprinkle of turmeric and black pepper
Sauté spinach in olive oil, toss in potatoes and heat until just warm. Top with protein, vinegar, and spices. Your gut and blood sugar will thank you.
I’ve put together a brand-new PDF exclusively for paid subscribers featuring 5 functional recipes that turn simple spuds into healing meals. From a savory frittata to gut-loving lentil soup, these recipes are designed to nourish your microbiome and support metabolic balance.
Upgrade today to unlock the full guide and bring the science of food to your plate.
References:
Nugent, A. P. (2005). Health properties of resistant starch. British Nutrition Foundation Nutrition Bulletin
Bodinham, C. L., et al. (2010). Short-term effects of resistant starch on insulin sensitivity. The American Journal of Clinical Nutrition
Bindels, L. B., et al. (2015). Gut microbiota-targeted dietary interventions: Impact on human metabolic disease. Molecular Metabolism
Sharma, A., et al. (2023). Effects of potato side dish consumption compared to refined grains on gut microbiota and metabolic markers in healthy adults: A randomized crossover trial. Nutrients, 15(4), 894. https://doi.org/10.3390/nu15040894
Sajilata, M. G., Singhal, R. S., & Kulkarni, P. R. (2006). Resistant starch – A review. Comprehensive Reviews in Food Science and Food Safety, 5(1), 1–17. https://doi.org/10.1111/j.1541-4337.2006.tb00076.x
Nilsson, A. C., et al. (2008). Glycemia and insulinemia in healthy subjects after lactose-equivalent meals of milk and other dairy products: The role of plasma insulin and incretin hormones. The American Journal of Clinical Nutrition, 87(4), 957–962.
Bindels, L. B., Delzenne, N. M., Cani, P. D., & Walter, J. (2015). Towards a more comprehensive concept for prebiotics. Nature Reviews Gastroenterology & Hepatology, 12(5), 303–310.
Bodinham, C. L., et al. (2010). Short-term effects of whole grain oat-based and wheat-based breakfast cereals on postprandial glucose and insulin responses in healthy subjects. British Journal of Nutrition, 103(7), 949–955.
Nugent, A. P. (2005). Health properties of resistant starch. British Nutrition Foundation Nutrition Bulletin, 30(1), 27–54.
Maziarz, M. P., et al. (2017). Cooking and cooling increase the formation of resistant starch in potatoes. Journal of Food Science, 82(12), 2880–2885.
Raben, A., et al. (1994). Resistant starch: The effect on postprandial glycemia, hormonal response, and satiety. The American Journal of Clinical Nutrition, 60(4), 544–551.