Does Sugar Cause IBS? Understanding the Connection Between Sweet Cravings and IBS

If you have Irritable Bowel Syndrome (IBS), you’ve probably ridden the rollercoaster of bloating, cramping, constipation, or diarrhoea — sometimes without any obvious cause. But what if your love for sugar is quietly behind those symptoms?

In this article, we’ll explore the evidence-based link between sugar and IBS, how different sugars affect your gut, and what you can do to reduce symptoms—without giving up everything sweet.

What Is IBS?

Irritable Bowel Syndrome (IBS) is a chronic functional gastrointestinal disorder marked by:

• Bloating
• Abdominal pain or cramping
• Excess gas
• Constipation, diarrhoea, or both

IBS stems from a mix of gut-brain axis dysfunction, low-grade inflammation, microbiome imbalance, and food sensitivities.

Why Sugar Can Trigger IBS Symptoms

You don’t need to eat a chocolate bar to set off IBS. Even “healthy” sugars like honey or fruit can cause trouble. Here’s why:

1. Fermentation by Gut Bacteria

Poorly absorbed sugars become food for gut bacteria in the colon, triggering:

• Gas and bloating
• Cramping and pain
• Diarrhoea due to water being pulled into the colon
• Worsened gut motility in SIBO or Candida overgrowth
• Heightened gut sensitivity in people with IBS or dysbiosis

Common fermentable sugars:

• Fructose
• Lactose
• Sorbitol
• Other FODMAPs

2. Osmotic Effects: How Sugar Causes Diarrhoea

Some sugars draw water into the gut through osmosis, leading to:

• Loose, urgent stools
• Abdominal discomfort
• Bloating

More likely in those with:

• Lactose intolerance
• Fructose malabsorption
• Sorbitol/mannitol sensitivity
• SIBO or Candida

3. Sluggish Motility: Why Sugar Can Also Cause Constipation

While sugar often causes diarrhoea in IBS due to its osmotic effects, it can also worsen constipation—especially in individuals with IBS-C (constipation-predominant IBS). Here’s how:

• Disrupts gut motility: Diets high in refined sugar and low in fibre can slow intestinal transit time, meaning food moves more slowly through the digestive tract.
• Dehydrates the colon: High-sugar foods often lack water and fibre, leading to dry, hard stools that are more difficult to pass.
• Alters microbiome composition: Excess sugar feeds opportunistic bacteria and yeasts like Candida, while reducing beneficial bacteria that support motility (e.g., Bifidobacterium). This microbial imbalance can further slow digestion.
• Feeds Candida and SIBO: Both conditions are known to affect intestinal movement and can be underlying contributors to constipation in IBS.

Signs sugar may be contributing to constipation:

• Infrequent bowel movements (fewer than 3 per week)
• Hard, pellet-like stools
• Straining during bowel movements
• A feeling of incomplete evacuation

Tip: If your IBS leans toward constipation, reducing sugar while increasing ydration, and prebiotic foods may support healthier bowel regularity.

4. Feeds Dysbiosis and Candida Overgrowth

Excess sugar feeds harmful bacteria and yeasts like Candida albicans, disrupting gut flora and driving IBS symptoms like:

• Bloating
• Constipation or diarrhoea
• Fatigue or brain fog
• Sugar cravings

Candida also influences cravings by hijacking your brain’s reward system, creating a vicious cycle of sugar dependence and gut distress.

5. Triggers Gut Inflammation and Leaky Gut

Sugar may contribute to:

• Increased gut permeability (“leaky gut”)
• Low-grade inflammation
• Immune activation and pain signaling

Types of Sugar Most Likely to Trigger IBS Symptoms

Not all sugars are equal. These are the most problematic for IBS sufferers:

Sugar, Candida, and IBS: The Hidden Link

Candida albicans thrives on sugar and can:

• Disrupt digestion
• Worsen IBS symptoms
• Trigger cravings
• Increase gut permeability

Signs Candida may be involved:

• Persistent sugar cravings
• Bloating or gas after sweets
• Brain fog or fatigue
• Thrush, yeast infections, or skin issues

Sugar and the FODMAP Diet

Many sugary foods are high-FODMAP, including:

• Excess fructose
• Lactose
• Polyols (sorbitol, mannitol)

A 2014 study in Gastroenterology found a low-FODMAP diet reduced IBS symptoms in over 70% of patients.

How Sugar Affects Gut Bacteria

Excess sugar can:

• Feed pro-inflammatory bacteria (like Firmicutes)
• Reduce beneficial bacteria (Lactobacillus, Bifidobacterium)
• Promote Candida and dysbiosis

Sugar and the Gut-Brain Axis

Sugar affects the gut-brain connection by:

• Spiking cortisol (stress hormone)
• Disrupting serotonin and GABA (gut-made neurotransmitters)
• Worsening anxiety, brain fog, and gut sensitivity

Does Sugar Cause Constipation or Diarrhoea?

It depends on the sugar type:

• Fructose & polyols → Diarrhoea (due to fermentation & osmosis)
• Low-fibre, high-sugar diets → Constipation (slows motility)

How to Tell If Sugar Is Triggering Your IBS

Ask yourself:

• Do I feel bloated, gassy, or crampy after sweet foods?
• Does fruit or sugar-free gum make me worse?
• Do symptoms flare after bread, cakes, or chocolate?
• Have I been diagnosed with lactose or fructose intolerance?

If yes to any — sugar may be playing a role.

What You Can Do: Practical Tips

1. Track your intake with a food & symptom diary
2. Cut high-FODMAP sugars: e.g. honey, apples, dairy, sorbitol
3. Try a low-FODMAP diet with expert guidance
4. Reduce refined sugar and ultra-processed foods
5. Support gut health with probiotics, prebiotics, enzymes, and nutrients
6. Book a consultation at our sister IBS Clinic-

Functional Testing for IBS, Candida & SIBO

You can also consider comprehensive testing to uncover sugar-related gut issues:

Candida Testing

• Stool analysis: Detects Candida overgrowth tests and yeast levels
• Urine organic acids test: Measures yeast metabolites like arabinose

SIBO Testing

• Consider a Hydrogen and Methane breath test for SIBO Lactulose or glucose breath test:
• Stool testing: Reveals dysbiosis, Candida, and more

Testing allows us to tailor a gut healing plan using diet, antifungal support, and microbiome-balancing strategies.

FAQs About Sugar and IBS

Q: Does sugar make IBS worse?
Yes, especially fructose and sugar alcohols.

Q: Can cutting out sugar help IBS?
Often, yes. Reducing sugar improves bloating, bowel movements, and energy.

Q: How do I test for sugar-related IBS issues?
SIBO breath testing, stool analysis, and Candida testing are most effective.

Q: Does sugar affect gut bacteria?
Yes, it can fuel dysbiosis and reduce beneficial bacteria.

Q: Are sugar cravings linked to IBS?
They can be. Often a sign of Candida or bacterial imbalance.

Final Thoughts

Sugar may feel harmless — or even comforting — but for many people with IBS, it’s quietly fueling gut chaos.

The good news? You don’t need to give up all sweet foods forever. With testing, targeted support, and a personalised approach, you can reduce symptoms, beat sugar cravings, and support long-term gut health.

References

1. Halmos, E.P., Power, V.A., Shepherd, S.J., Gibson, P.R., & Muir, J.G. (2014). A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology, 146(1), pp.67–75.e5. https://doi.org/10.1053/j.gastro.2013.09.046
2. Shepherd, S.J. & Gibson, P.R. (2006). Fructose malabsorption and symptoms of irritable bowel syndrome: Guidelines for effective dietary management. Journal of the American Dietetic Association, 106(10), pp.1631–1639. https://doi.org/10.1016/j.jada.2006.07.012
3. Staudacher, H.M., et al. (2017). Mechanisms and efficacy of dietary FODMAP restriction in IBS. Nature Reviews Gastroenterology & Hepatology, 14(7), pp.406–418. https://doi.org/10.1038/nrgastro.2017.97
4. Pimentel, M., Lembo, A., & Chey, W.D. (2020). Small intestinal bacterial overgrowth: A framework for understanding IBS. Nature Reviews Gastroenterology & Hepatology, 17(6), pp.347–359. https://doi.org/10.1038/s41575-020-0274-0
5. Miller, L.E. & Ouwehand, A.C. (2013). Probiotic supplementation decreases intestinal transit time: Meta-analysis of randomized controlled trials. World Journal of Gastroenterology, 19(29), pp.4718–4724. https://doi.org/10.3748/wjg.v19.i29.4718
6. Seitz, J., Trinh, S., & Herpertz-Dahlmann, B. (2020). The microbiome and eating disorders. Psychiatria Danubina, 32(Suppl 2), pp.153–157. PubMed
7. Tana, C., et al. (2010). Altered gut microbiota in irritable bowel syndrome: What’s the link with diet? International Journal of Obesity, 34(S2), pp.S34–S40. https://doi.org/10.1038/ijo.2010.86
8. Morris, G., et al. (2017). The role of microbiota and intestinal permeability in the pathophysiology of autoimmune and neuroimmune processes. Molecular Neurobiology, 54(6), pp.4432–4451. https://doi.org/10.1007/s12035-016-0007-4
9. Berni Canani, R., et al. (2016). Role of probiotics in the treatment of gastrointestinal disorders in children. Nutrition, 32(3), pp.309–317. https://doi.org/10.1016/j.nut.2015.09.009

Author – Victoria Tyler BSc Hons MBANT

Victoria Tyler owns and runs two busy clinics : Nutrition and Vitality and the IBS and Gut Disorder Clinic.

Nutrition and Vitality, along with the IBS and Gut Disorder Clinic, were founded with the goal of helping patients alleviate IBS symptoms by uncovering and addressing the root causes of their digestive issues.

As a Registered Nutritional Therapist, Victoria holds a BSc (Hons) in Nutritional Therapy and has trained with the Institute of Functional Medicine. She is also accredited by BANT and CNHC.

Before transitioning into health, Victoria earned a degree in Economics and an MBA, working with corporations including Canon and Vodafone. However, her own health challenges led her to pursue a career in Nutritional Therapy.

With a passion for learning, Victoria is committed to staying at the forefront of Functional Medicine. She helps patients manage IBS and other digestive disorders, including SIBO, Candida, and IBD, by identifying and addressing their root causes.

Victoria strongly believes that every symptom has an underlying cause, and there is always a solution to every health condition. To learn more, or to see patient reviews, visit Victoria’s profile on Google.

DISCLAIMER: The information provided in this article is intended for general informational purposes only and should not be construed as medical advice, diagnosis, or treatment. The products and methods mentioned are not a substitute for professional medical advice from a trained healthcare specialist. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. Use of the information and products discussed is at your own risk.

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