Why Does My Stomach Ache When I Eat Sugar?

January 3, 2026 •

4 min read

According to the National Institutes of Health, up to 65% of the world's population experiences some level of lactose intolerance, a form of sugar intolerance. Similarly, many people wonder, "Why does my stomach ache when I eat sugar?" The discomfort can stem from several factors, including imbalances in gut bacteria, fermentation of undigested sugars, or underlying conditions like fructose malabsorption.

Quick Summary

Stomach pain after consuming sugar can result from conditions like fructose malabsorption, an imbalance of gut bacteria feeding on undigested sugar, and irritable bowel syndrome. The digestive tract can react negatively to both natural and artificial sugars, leading to symptoms such as cramping, bloating, and gas.

Key Points

Gut Bacteria Imbalance: High sugar intake can cause dysbiosis, an imbalance in gut bacteria that promotes harmful microbes and triggers inflammation.
Fructose Malabsorption: Your small intestine may fail to properly absorb fructose, leading to fermentation by gut bacteria and symptoms like gas and cramping.
Sucrose Intolerance: A deficiency in the enzyme sucrase-isomaltase can prevent the breakdown of table sugar, causing pain and bloating.
IBS and FODMAPs: Certain sugars are high-FODMAPs that can trigger or worsen symptoms in individuals with Irritable Bowel Syndrome.
Sugar Alcohols: Artificial sweeteners like sorbitol and xylitol are poorly absorbed and can cause significant digestive distress.
Gas and Bloating: When undigested sugar reaches the large intestine, bacteria ferment it, producing gas that leads to bloating and pain.
Dietary Management: Keeping a food diary, prioritizing fiber, and staying hydrated are effective strategies for managing sugar-related stomach aches.

Understanding Sugar's Impact on Your Digestive System

When you consume sugar, your body's digestive system, particularly the small intestine, breaks it down with enzymes for absorption. However, this process doesn't always go smoothly. Several factors can lead to sugar passing into the large intestine undigested, where resident bacteria ferment it. This fermentation process creates gas, leading to bloating, cramping, and pain. The reasons behind this improper digestion can range from enzyme deficiencies to more complex gastrointestinal disorders.

Gut Bacteria Imbalance (Dysbiosis)

Your gut contains trillions of microorganisms, collectively known as the gut microbiome. This delicate ecosystem plays a crucial role in digestion and overall health. A diet high in refined and added sugars can disrupt this balance, a condition known as dysbiosis. Excessive sugar intake can feed harmful bacteria and yeast, like Candida, causing them to multiply and overpower beneficial bacteria. This imbalance can trigger inflammation and various digestive issues, including stomach pain.

Fructose Malabsorption

Fructose is a simple sugar found in fruits, honey, high-fructose corn syrup, and many processed foods. For some individuals, the cells in the small intestine struggle to absorb fructose efficiently. When this happens, the unabsorbed fructose travels to the large intestine, where it is fermented by bacteria, causing gas, bloating, diarrhea, and stomach pain. Fructose malabsorption is thought to affect a significant portion of the population and can often mimic symptoms of Irritable Bowel Syndrome (IBS).

Sucrase-Isomaltase Deficiency (CSID) or Sucrose Intolerance

Sucrose, or table sugar, is a disaccharide made of glucose and fructose. It is broken down by the enzyme sucrase-isomaltase in the small intestine. In rare cases, a person is born with or acquires a deficiency of this enzyme, leading to an inability to properly digest sucrose. This results in symptoms similar to IBS, including abdominal pain, gas, and diarrhea, especially in adults who acquire the condition due to other gastrointestinal damage. Treatment often involves enzyme replacement therapy or dietary modifications to reduce sucrose intake.

Irritable Bowel Syndrome (IBS) and FODMAPs

IBS is a chronic gastrointestinal disorder that affects the large intestine, causing cramps, bloating, and changes in bowel habits. For many people with IBS, consuming certain types of carbohydrates, including specific sugars, can trigger or worsen symptoms. Sugars are part of a group of fermentable carbohydrates known as FODMAPs. Reducing high-FODMAP foods and managing overall sugar intake is a key dietary strategy for managing IBS symptoms.

The Issue with Sugar Alcohols

Many sugar-free or low-calorie products contain artificial sweeteners known as sugar alcohols, such as sorbitol, xylitol, and mannitol. The body does not easily absorb these sweeteners, and they can have a laxative effect or cause bloating and cramping. Even for those without a specific sugar intolerance, consuming large amounts of sugar alcohols can lead to significant digestive discomfort.

How to Manage Your Sugar-Related Stomach Ache

If you consistently experience a stomach ache after eating sugar, here are some actionable steps you can take:

Keep a Food Diary: Track your meals, noting the types of sugar and artificial sweeteners consumed, and correlate them with any resulting digestive symptoms.
Prioritize Fiber: Increase your intake of fiber-rich whole foods like fruits, vegetables, and whole grains. Fiber can help regulate digestion and slow the absorption of sugars.
Stay Hydrated: Drinking plenty of water can help flush your system and dilute the concentration of sugars, potentially easing discomfort.
Drink Herbal Tea: Sipping on herbal teas like peppermint or chamomile can help reduce gas and soothe an upset stomach.
Mindful Eating: Eat slowly and chew your food thoroughly to aid digestion.
Consider Elimination: Try a temporary elimination diet to identify specific sugar triggers, or consider a low-FODMAP diet under the guidance of a healthcare professional.

Comparison of Different Sugar-Related Stomach Issues


Feature	Fructose Malabsorption	Sucrose Intolerance (CSID)	General Excess Sugar	Gut Microbiome Imbalance
Cause	Impaired transport of fructose in the small intestine.	Deficiency of the sucrase-isomaltase enzyme.	Overwhelming the digestive system with too much sugar at once.	Shift in bacteria, favoring harmful microbes over beneficial ones.
Trigger	High-fructose foods (fruit, honey, HFCS).	Sucrose (table sugar) and sometimes maltose.	Any source of excess sugar, especially added or refined sugar.	Long-term, high intake of refined and added sugars.
Symptoms	Gas, bloating, diarrhea, cramps.	Abdominal pain, bloating, gas, diarrhea.	Bloating, cramping, gas, nausea.	Bloating, gas, irregular bowel movements, inflammation.
Onset	Usually shortly after eating the triggering food.	Immediately after consuming sucrose.	Shortly after consuming a large amount of sugar.	Can be a chronic, long-term issue.
Treatment	Dietary modifications (low-fructose diet), breath test diagnosis.	Enzyme therapy (Sucraid), dietary changes.	Portion control, mindful eating, healthier swaps.	Probiotics, prebiotics, and low-sugar diet to rebalance the gut.

Conclusion

Experiencing a stomach ache after eating sugar is a common yet uncomfortable issue that points to an underlying digestive problem. Whether it's a specific intolerance to certain sugars like fructose or sucrose, an imbalanced gut microbiome caused by excessive intake, or an exacerbation of an existing condition like IBS, the result is fermentation in the large intestine and subsequent pain. Managing your sugar intake, understanding your personal triggers, and making thoughtful dietary swaps can help mitigate symptoms and improve your overall digestive health. For persistent or severe symptoms, consulting a healthcare provider or a gastroenterologist is essential for accurate diagnosis and a personalized treatment plan.

Visit Healthline for more detailed information on types of sugar that may trigger IBS symptoms.

Frequently Asked Questions

A sugar intolerance is a digestive issue where the body cannot properly break down a certain sugar, causing symptoms like gas and bloating. A sugar allergy is a more severe immune system response to a food protein and can cause life-threatening reactions, though a sugar allergy is very rare.

Yes, many artificial sweeteners, particularly sugar alcohols such as sorbitol and xylitol, are not fully absorbed by the body. They can ferment in the gut, leading to gas, bloating, cramping, and even a laxative effect.

When the small intestine can't absorb all the sugar consumed, the undigested sugar travels to the large intestine. Here, bacteria feed on the sugar and produce gas as a byproduct, resulting in bloating and painful gas.

While excessive sugar intake is a risk factor for diabetes, a stomach ache from sugar is not a direct symptom. The pain is typically caused by digestive issues like gut bacteria imbalance or sugar intolerance rather than blood sugar levels.

Fructose malabsorption is a condition where the body has difficulty absorbing fructose, a type of sugar found in fruits, honey, and high-fructose corn syrup. The unabsorbed fructose ferments in the gut, causing digestive symptoms.

For immediate relief, you can try sipping water, drinking herbal teas like peppermint or ginger, and taking a short, gentle walk. Over-the-counter remedies like Gas-X may also help break down gas bubbles.

Yes, a sugar intolerance can coexist with or even contribute to IBS symptoms. Many people with IBS are sensitive to certain sugars (FODMAPs) like fructose and lactose, and identifying and limiting these can help manage symptoms.