Is pasta healthier the day after? The surprising science of resistant starch

October 30, 2025 •

3 min read

According to a 2014 BBC-funded study, cooking, cooling, and then reheating pasta can reduce the post-meal blood glucose increase by up to 50% compared to freshly cooked pasta. This astonishing finding answers the question, 'Is pasta healthier the day after?' with a resounding 'yes,' thanks to the formation of a beneficial compound called resistant starch.

Quick Summary

The process of cooking and cooling starchy foods like pasta converts some digestible starch into resistant starch, a type of fiber that benefits blood sugar control and gut health. Reheating this cooled pasta enhances the effect, offering metabolic advantages over eating it freshly prepared. Key to this nutritional hack is proper refrigeration to ensure food safety.

Key Points

Resistant Starch Boosts Nutrition: Cooling and reheating cooked pasta increases its resistant starch content, a type of fiber that resists digestion.
Lowers Blood Sugar Spikes: The presence of resistant starch leads to a lower and more gradual rise in blood glucose levels after eating.
Feeds Healthy Gut Bacteria: Resistant starch acts as a prebiotic, fermenting in the large intestine to nourish beneficial gut microbes.
Reheating Amplifies Benefits: Some studies show that reheated, cooled pasta has an even smaller effect on blood sugar than simply chilled pasta.
Proper Storage is Essential: To prevent foodborne illness, cooked pasta must be cooled quickly and refrigerated properly, reaching a safe internal temperature upon reheating.
Weight Management Support: By promoting feelings of fullness, resistant starch may help reduce overall calorie intake and support weight management.

The Science Behind a Healthier Leftover

When starchy foods like pasta are cooked, their starches are easily digested and can cause rapid increases in blood sugar. However, cooling cooked pasta initiates a process called starch retrogradation. During this time, the starch molecules reorganize into a structure that is more resistant to digestion. This transformed starch is known as 'resistant starch' (RS3), and it acts similarly to dietary fiber because it passes through the small intestine mostly undigested.

Resistant starch then reaches the large intestine, where it is fermented by beneficial gut bacteria. This fermentation produces short-chain fatty acids (SCFAs), such as butyrate, which are linked to various health benefits, including reduced inflammation and a healthier gut microbiome.

The Surprising Effect of Reheating

A study highlighted on the BBC's Trust Me I'm a Doctor investigated the impact of reheating cooled pasta. The findings indicated that consuming reheated, cooled pasta resulted in an even lower blood glucose spike compared to eating it cold. This suggests that the cycle of cooking, cooling, and reheating can further enhance the benefits of resistant starch. Thus, you can still enjoy warm pasta leftovers while potentially gaining greater metabolic advantages.

Health Benefits of Boosting Resistant Starch

Consuming leftover pasta can provide several health benefits due to its increased resistant starch content:

Improved Blood Sugar Control: Resistant starch helps moderate the rate at which glucose enters the bloodstream, preventing sharp rises and falls in blood sugar levels. This is advantageous for managing conditions like diabetes and maintaining consistent energy levels.
Better Gut Health: By serving as a food source for beneficial gut bacteria, resistant starch supports a balanced and diverse gut microbiome. A healthy gut is associated with improved digestion, reduced inflammation, and enhanced immune function.
Increased Satiety: Resistant starch contributes to a feeling of fullness that can last longer than that from easily digestible starches. This prolonged satiety may help decrease overall calorie consumption and support weight management efforts.
Lowered Inflammation: The SCFAs produced during the fermentation of resistant starch possess anti-inflammatory properties, contributing to overall metabolic and cardiovascular well-being.

How to Prepare Healthier Leftover Pasta

To maximize the resistant starch in your pasta, follow these steps:

Cook Al Dente: Avoid overcooking; cook pasta until it is firm to the bite.
Cool Quickly: Drain and cool the pasta rapidly, perhaps by spreading it out or rinsing with cold water. A little olive oil can prevent sticking.
Refrigerate for 24 Hours: Store in an airtight container in the refrigerator for at least 12–24 hours to allow resistant starch to develop.
Reheat Gently: Reheat the cooled pasta carefully to avoid high temperatures that could damage the resistant starch structure. Use a microwave with added water or sauté lightly.

Food Safety Precautions for Leftovers

Ensuring food safety is crucial when dealing with leftovers, especially pasta and rice, which can harbor Bacillus cereus, a bacterium that can cause food poisoning if not handled correctly.

Prompt Refrigeration: Always refrigerate cooked pasta within two hours.
Small Containers: Use shallow, airtight containers for refrigeration to promote quick and even cooling.
Reheat Thoroughly: Ensure leftovers are heated until steaming hot throughout, reaching an internal temperature of 165°F (75°C).
Reheat Only Once: It's recommended to reheat leftovers only one time for safety.

Fresh vs. Leftover Pasta: A Comparison


Feature	Freshly Cooked Pasta	Cooked & Cooled Pasta	Cooled & Reheated Pasta
Starch Type	Readily digestible starch	Increased resistant starch	Enhanced resistant starch
Glycemic Impact	Higher blood sugar spike	Moderate blood sugar spike	Lower blood sugar spike
Digestion Speed	Faster digestion	Slower digestion	Slower digestion
Gut Health	Minimal impact on gut bacteria	Acts as a prebiotic	Acts as a prebiotic
Satiety Level	Standard feeling of fullness	Higher feeling of fullness	Higher feeling of fullness
Preparation Time	Cook and serve immediately	Requires additional 12-24 hrs for cooling	Requires cooling time and gentle reheating

Conclusion: A Simple Trick for a Healthier Meal

Evidence suggests that enjoying leftover pasta can provide nutritional advantages compared to eating it freshly prepared. By cooking, cooling, and gently reheating pasta, you can increase its resistant starch content. This type of fiber contributes to more stable blood sugar levels, supports a healthy gut microbiome, and promotes feelings of fullness. While not a complete solution for dietary health, this simple method offers an easy way to enhance the nutritional value of your meal. Remember to always prioritize food safety by following proper cooling and reheating guidelines. You can find more information about resistant starch and fiber on the American Diabetes Association website.

Frequently Asked Questions

When cooked pasta cools down, a process called retrogradation occurs where the starch molecules re-arrange into a more compact, crystalline structure that is resistant to digestion by the body's enzymes.

No, reheating does not destroy the resistant starch. In fact, some research suggests that the cook-cool-reheat cycle may even enhance its effects on blood sugar control, making it more beneficial than freshly cooked pasta.

Yes, this process of increasing resistant starch by cooking and cooling also works with other starchy foods like rice, potatoes, and oats.

For optimal resistant starch formation, it is recommended to refrigerate cooked pasta for at least 12 to 24 hours.

Yes, it is safe to eat cold pasta as long as it has been cooked thoroughly, cooled properly, and refrigerated promptly within two hours of cooking to prevent bacterial growth. Many people enjoy it in pasta salads.

While resistant starch contains fewer calories per gram than regular starch, the overall calorie reduction is typically modest. The primary benefits are related to blood sugar control, gut health, and satiety, not a drastic calorie change.

To preserve the resistant starch and maintain texture, reheat cooled pasta gently. Use the microwave with a splash of water or sauté it lightly in a pan on low-to-medium heat. Avoid re-boiling, as high heat can reverse the starch's beneficial structure.