Is starch good for a bad stomach? The digestive benefits and drawbacks

December 4, 2025 •

4 min read

The well-known BRAT diet, which stands for Bananas, Rice, Applesauce, and Toast, is a common recommendation for upset stomachs, but is starch good for a bad stomach in all its forms? The answer depends largely on the type of starch and your individual digestive sensitivity, as some are incredibly soothing while others can trigger uncomfortable symptoms.

Quick Summary

The impact of starch on an upset stomach varies significantly based on its type. Simple, digestible starches are often soothing and binding, while fermentable resistant starches can cause gas and bloating. Selecting the right starch is crucial for managing digestive discomfort and supporting gut health.

Key Points

Not All Starches are Equal: There's a crucial difference between rapidly digestible starches (RDS) and resistant starches (RS) for a sensitive stomach.
Simple Starches are Soothing: Foods with RDS, like white rice and toast, are easy to digest and can help bind stools, providing relief from diarrhea.
Resistant Starch Can Cause Bloating: RS ferments in the large intestine, producing gas that can cause pain and bloating, especially for those with IBS or a sensitive gut.
The BRAT Diet is Based on RDS: The effectiveness of the BRAT diet for an upset stomach comes from its use of simple, easy-to-digest starches.
Personal Tolerance Varies: The key to incorporating starch back into your diet after an upset stomach is to start with simple options and reintroduce more complex starches gradually.
Resistant Starch is Good for Long-Term Gut Health: While problematic during a flare-up, RS acts as a prebiotic for beneficial gut bacteria, making it healthy for a settled digestive system.

Understanding the Two Types of Starch

Not all starches are created equal when it comes to digestive health. Starches are carbohydrates composed of glucose molecules, but how they are structured determines how easily our bodies can break them down. When dealing with an upset stomach, distinguishing between rapidly digestible starch (RDS) and resistant starch (RS) is key to making the right dietary choices.

Rapidly Digestible Starch (RDS)

RDS is found in foods like white rice, white bread, crackers, and cooked potatoes. These starches are quickly and efficiently broken down by enzymes in the small intestine into glucose, providing a readily available source of energy. For a sensitive or upset stomach, RDS is often recommended because:

It is easy to digest: The body expends less energy and effort to process these foods, reducing stress on a compromised digestive system.
It can bind stools: Simple starches, like those found in the BRAT diet, can help firm up loose stools, offering relief from diarrhea.
It is non-fermentable: Because it is digested in the small intestine, RDS does not reach the large intestine to be fermented by gut bacteria, which prevents excess gas and bloating.

Resistant Starch (RS)

Resistant starch, as its name suggests, 'resists' digestion in the small intestine and instead travels to the large intestine, where it is fermented by gut bacteria. This fermentation process has significant health benefits, like producing beneficial short-chain fatty acids (SCFAs), but can also cause issues for sensitive guts. Foods high in resistant starch include:

Green (unripe) bananas
Cooked and cooled potatoes, rice, and pasta
Beans, lentils, and other legumes
Some oats and whole grains

The Soothing Role of Simple Starches

For many with a bad stomach, simple starches act as a gentle, comforting food that helps settle the digestive tract. When the gut is inflamed or irritated, heavy foods rich in fat, protein, and fiber can be difficult to process, leading to further discomfort. Simple starches provide an alternative that offers several benefits:

Nutrient replenishment: Vomiting or diarrhea can cause a loss of electrolytes. While not a cure, foods like plain toast can help provide some calories and energy without overwhelming the system.
Stomach-coating effect: Soft, plain starches may help coat the lining of the stomach, soothing irritation and easing digestion.
Versatility: Foods like plain rice porridge, or kanji, are staples for those with digestive upset due to their simple, nourishing, and hydrating qualities.

The Fermentation Factor of Resistant Starch

While resistant starch is excellent for long-term gut health, it can be a source of distress during a flare-up of stomach problems. The fermentation of RS by gut bacteria produces gases like hydrogen and methane. For individuals with sensitive bowels, irritable bowel syndrome (IBS), or other digestive disorders, this can lead to uncomfortable symptoms.

This fermentation process can cause:

Increased gas and flatulence
Abdominal bloating and distension
Pain and cramps due to trapped gas

Therefore, a person recovering from a stomach bug or dealing with a bout of IBS should generally avoid high-resistant starch foods and reintroduce them slowly as their symptoms subside. It's about personal tolerance and timing.

Comparing Starches for a Sensitive Stomach


Feature	Simple Starch (e.g., White Rice, Toast)	Resistant Starch (e.g., Cooled Potatoes, Green Bananas)
Digestibility	High, rapidly digested in the small intestine.	Low, resists digestion and ferments in the large intestine.
Fermentation	Minimal to none.	High, actively fermented by gut bacteria.
Symptom Impact	Soothing, binding, and low-risk for most.	Can cause gas, bloating, and pain in sensitive individuals.
Best For	Acute upset stomachs, diarrhea, post-illness recovery.	Promoting long-term gut health, feeding beneficial bacteria.
Glycemic Impact	Higher glycemic index (faster blood sugar spike).	Lower glycemic impact (slows sugar release).
Key Consideration	Excellent for short-term relief.	Introduce gradually once stomach is settled.

Dietary Recommendations for Starchy Foods

Choosing the right starchy foods requires a personalized approach, especially when experiencing digestive issues. Here are some practical tips:

Stick to Plain: When your stomach is upset, opt for plain, cooked starches. Boiled or steamed white rice, white toast, and crackers are good starting points.
Remove Skins: The skins of potatoes and other vegetables contain fiber that can be harder to digest. Peeling them makes the starch easier on the stomach.
Mind the Temperature: Be aware of how cooking and cooling affect starches. Cooked and cooled starches, while beneficial for the long term, are not ideal for an upset stomach because of the increase in resistant starch.
Go Low-FODMAP: For those with IBS, many low-FODMAP starches can be a safe bet. Plain cooked rice and quinoa are good examples.
Hydrate: Don't forget to drink plenty of water or clear broths, especially if experiencing diarrhea, to help with digestion and rehydration.

The Role of Starch in Gut Health

It is important to remember that resistant starch is not inherently 'bad' for the gut. For a healthy digestive system, it acts as a prebiotic, feeding beneficial bacteria in the colon and contributing to a balanced gut microbiome. A balanced microbiome is essential for overall health, influencing everything from immune function to mood. The key takeaway is to choose your starches strategically based on your current digestive state.

Conclusion: Listen to Your Body

Ultimately, whether starch is good for a bad stomach depends on the type of starch and your body's specific reaction. For immediate relief from symptoms like diarrhea and nausea, simple starches found in the BRAT diet are a time-tested and gentle solution. However, individuals with persistent gut sensitivity or conditions like IBS may need to be cautious with fermentable resistant starches, which can cause bloating and gas. The pathway to using starch for gut health is one of careful observation and gradual reintroduction. By understanding the difference between simple and resistant starches, you can make informed choices to soothe your stomach and support your digestive wellness.

For more in-depth scientific research on the effects of resistant starch and gut health, a clinical trial evaluated the gastrointestinal impact of varying doses of a resistant starch blend, finding it beneficial for long-term gut support.

Frequently Asked Questions

Plain, cooked simple starches are your best bet. Think plain white rice, white toast, crackers, and peeled, boiled potatoes. These are easily digestible and least likely to cause further irritation.

Yes, but with caution. Boiled or baked potatoes without the skin are generally safe because they contain easily digestible starch. Avoid skins, as they are high in fiber, and do not eat them cooked and cooled, as this increases resistant starch.

Resistant starch passes through the small intestine undigested and is fermented by gut bacteria in the large intestine. This fermentation produces gas, which can lead to bloating, pain, and discomfort for those with a sensitive or inflamed digestive system.

For an upset stomach, white rice is generally preferred. Brown rice is a whole grain containing fiber that can be difficult for a sensitive gut to process, while white rice is a simple starch that is easier to digest.

If your symptoms, such as bloating and gas, worsen after consuming foods like beans, lentils, or day-old pasta, the fermentable resistant starch may be the culprit. Keeping a food diary can help you identify triggers and patterns.

No, you don't need to avoid all starch. Simple starches are often part of a recovery diet, like the BRAT diet, because they are gentle and provide energy. The key is to select easily digestible starches and avoid more complex ones.

Once your stomach has settled, gradually reintroduce resistant starch in small amounts. For example, add a small portion of lentils to a meal or eat a small helping of cooled rice. Observe how your body reacts before increasing the quantity.