Is Starch in Potatoes Bad for Your Stomach?

November 18, 2025 •

4 min read

Over 7,000 years, potatoes have been a global staple, yet their high starch content often sparks questions about digestive health. For most people, starch in potatoes is not bad for your stomach, but its effects vary greatly depending on how the potato is prepared and your individual tolerance.

Quick Summary

The impact of potato starch on digestion depends largely on whether the potato is cooked or raw. Cooked and cooled potatoes produce resistant starch, a prebiotic that supports gut bacteria, while raw potatoes are harder to digest and can cause issues like gas and bloating due to higher levels of resistant starch and other compounds.

Key Points

Cooked and cooled potatoes are best: The cooling process converts some digestible starch into resistant starch, which benefits gut health.
Raw potatoes are harmful: They are difficult to digest and contain higher levels of toxic glycoalkaloids that cooking neutralizes.
Resistant starch is a prebiotic: It feeds beneficial gut bacteria, which in turn produce health-promoting short-chain fatty acids like butyrate.
Gradual increase is advised: Introducing resistant starch slowly helps prevent common side effects like gas and bloating.
Cooking method matters: Boiling or steaming potatoes is healthier and easier on the stomach than frying, which can add unnecessary fats.
Avoid green or sprouted parts: These areas of the potato contain elevated levels of toxins that can cause stomach issues.
Resistant starch can be reheated: Gentle reheating in a microwave or pan does not eliminate the resistant starch benefits.

Understanding Potato Starch and Your Digestion

Potato starch, a complex carbohydrate, is broken down by the body into glucose for energy. However, its digestive properties are not static. They change dramatically with preparation, particularly through cooking and cooling. The key to understanding whether potato starch is good or bad for your stomach lies in recognizing the difference between digestible starch and resistant starch.

The Impact of Cooking and Cooling

When a potato is cooked, its starch granules undergo a process called gelatinization, making them easily digestible by enzymes in the small intestine. This is the starch found in hot mashed potatoes or french fries. For most people, this form of starch is readily processed without issue, providing a quick source of energy.

Conversely, when a cooked potato is cooled, some of its digestible starch undergoes retrogradation and becomes resistant starch. This type of starch is a non-digestible fiber that travels to the large intestine, where it becomes a food source for beneficial gut bacteria.

Raw potato: Contains a high amount of Type 2 resistant starch, which is difficult for the human digestive system to break down and can cause significant stomach upset, gas, and bloating. Raw potatoes also contain higher levels of glycoalkaloids and anti-nutrients, which are minimized with cooking.
Hot, cooked potato: The starch is easily digested and absorbed as glucose, which can cause a rapid spike in blood sugar.
Cooked and cooled potato: This process creates Type 3 resistant starch, which acts as a prebiotic. It ferments slowly in the large intestine, feeding good bacteria and minimizing the gas and discomfort associated with rapid fermentation.

The Role of Resistant Starch

Resistant starch acts as a prebiotic, and its fermentation by gut bacteria produces beneficial short-chain fatty acids (SCFAs), particularly butyrate. Butyrate is the preferred energy source for the cells lining the colon and has anti-inflammatory properties, strengthening the gut barrier and potentially protecting against diseases like colorectal cancer and inflammatory bowel disorders. A healthy and diverse gut microbiome is critical for realizing these benefits, as different types of bacteria cooperate to ferment the resistant starch.

Potential Digestive Issues

While resistant starch is beneficial for gut health, introducing large amounts too quickly can cause digestive problems, especially for sensitive individuals. The fermentation process naturally produces gas, which can lead to bloating, discomfort, and flatulence. The best practice is to increase your intake gradually to allow your system to adjust.

Comparison of Potato Starch Digestibility


Feature	Raw Potato Starch	Cooked, Hot Potato Starch	Cooked, Cooled Potato Starch
Digestibility	Very difficult to digest; high in Type 2 resistant starch.	Readily digestible; converted to glucose quickly.	Moderately resistant; forms Type 3 resistant starch.
Primary Effect	Potential for significant stomach upset, gas, and bloating.	Provides immediate energy and can cause a blood sugar spike.	Acts as a prebiotic, feeding beneficial gut bacteria over time.
Gut Impact	Can produce uncomfortable gas from fermentation, along with other harmful compounds.	Minimal fermentation in the large intestine.	Promotes gut microbial diversity and produces beneficial SCFAs.
Safety	Considered unsafe due to higher levels of toxins like solanine and anti-nutrients.	Generally safe for most people, though moderation is key.	Very safe and beneficial for most people, especially for gut health.

Other Factors Affecting Digestion

Several other elements influence how potatoes affect your stomach beyond just starch content and preparation method:

Glycoalkaloids: Green potatoes and sprouts contain higher levels of solanine and other toxins, which can cause significant gastrointestinal distress, including vomiting and diarrhea. It is crucial to properly store potatoes in a cool, dark place and to cut off any green or sprouted parts before cooking.
Cooking Method: Fried potatoes, high in added fats and potential acrylamides, are not only less healthy but also harder to digest than steamed or boiled potatoes. The added fats can contribute to indigestion and abdominal pain.
FODMAPs and IBS: While plain white potatoes are low in FODMAPs (fermentable carbs that can trigger IBS symptoms), some individuals with Irritable Bowel Syndrome may still experience sensitivity. Sweet potatoes contain moderate levels of FODMAPs at larger serving sizes. As with any food, personal tolerance is key.
Fiber Content: Leaving the skin on provides more fiber, which can aid digestion and gut health, especially when the potato has been cooked and cooled to increase its resistant starch.

Conclusion

Starch in potatoes is not inherently bad for your stomach. The key is in preparation and moderation. Cooked and cooled potatoes are a rich source of resistant starch, a prebiotic that nourishes your gut bacteria, leading to a host of health benefits. Conversely, eating raw potatoes should be avoided due to toxins and difficult-to-digest starch. For sensitive individuals or those with IBS, paying attention to cooking methods and portion sizes is important. By cooking potatoes properly, you can turn a common vegetable into a valuable ally for digestive health, rather than a foe.

For more information on the types of resistant starch and their effects on health, you can consult research from the National Institutes of Health (NIH).

Frequently Asked Questions

For some people, especially those unaccustomed to it, resistant starch from potatoes can cause bloating and gas. This is because the beneficial bacteria in the large intestine ferment the starch, a process that naturally produces gas. Starting with small amounts can help your digestive system adjust.

Most plain white potatoes are low FODMAP and generally safe for those with IBS. However, individual sensitivity varies. While resistant starch ferments more slowly and is often better tolerated than FODMAPs, some people may still experience symptoms. It's best to test your personal tolerance with small portions.

When potatoes are cooked and hot, their starch is easily digestible, leading to a quicker blood sugar spike. When cooled, some of this starch becomes resistant starch, which is not digested in the small intestine. This resistant starch feeds healthy gut bacteria and has a lower glycemic impact.

Raw potato starch is a concentrated source of resistant starch, but it can be very difficult to digest in its raw form and may cause significant discomfort. A better approach for increasing resistant starch intake is to cool cooked potatoes or other starchy foods.

Peeling potatoes does not significantly change their starch content. The skin is a source of dietary fiber and nutrients like potassium, which can benefit digestive health. However, you should always remove any green or sprouted parts, as these contain high levels of toxins.

Yes, you can gently reheat cooked and cooled potatoes without losing the resistant starch. Using a microwave or a low heat on the stove is best to maintain the beneficial properties.

Fried potatoes are less beneficial for gut health than boiled or steamed potatoes. The added fats and oils can be harder to digest and may contribute to stomach upset and indigestion, especially for those with sensitive digestive systems.