Why IBS Symptoms Can Change Over Time

The Tummy Clinic | March 23rd, 2026

One of the most confusing aspects of IBS is that symptoms can change.

Patients often describe experiences such as:

“Last year I had constipation. Now I have urgency.”

“I used to struggle mainly with bloating. Now I feel nauseated after meals.”

“It feels like something new is always going wrong with my digestion.”

These shifting patterns are extremely common in IBS and are actually a reflection of how the digestive system works.

IBS is a disorder of regulation

IBS is not a structural disease. Instead, it involves changes in how the digestive system regulates movement, sensation, and communication with the brain.

Several systems interact in this process, including:

  • intestinal motility
  • gut–brain communication
  • microbial fermentation in the colon
  • immune signaling in the gut lining
  • sensory perception from the digestive tract

Because these systems interact constantly, symptoms can shift depending on which part of the system is most active at a given time.

The digestive system is dynamic

The digestive tract is one of the most responsive systems in the body.

It continuously responds to signals from:

  • food
  • stress
  • sleep patterns
  • hormones
  • immune activity
  • the nervous system

As these signals change, the digestive system adjusts its activity.

In people with IBS, these adjustments can sometimes become exaggerated or poorly coordinated, which may produce symptoms such as:

  • constipation
  • urgency
  • bloating
  • abdominal pain
  • nausea
  • early fullness

Symptoms shifting does not mean something new is wrong

One of the most important messages for patients to understand is that shifting symptoms are common in IBS.

A change in symptom pattern does not necessarily mean that a new disease has developed.

Instead, it often reflects the dynamic nature of gut regulation.

Once other medical conditions have been appropriately ruled out, the focus of care usually shifts toward stabilizing the digestive system rather than repeatedly searching for new diagnoses.

Visceral hypersensitivity

Another important factor in IBS is visceral hypersensitivity.

This means that the nerves in the digestive tract become more sensitive to normal signals.

A normal amount of gas or intestinal movement that most people would barely notice may feel uncomfortable or painful in someone with IBS.

This heightened sensitivity can make symptoms feel unpredictable and alarming.

Understanding this mechanism can help patients recognize that symptoms do not necessarily indicate damage or disease progression.

Clinical Perspective by
Dr. Tracey Beaulne, ND
Co-Founder, The Tummy Clinic

Dr. Tracey Beaulne, ND
Co-Founder of The Tummy Clinic, a virtual clinic focused on evidence-based care for Disorders of Gut–Brain Interaction (DGBIs), including IBS. Dr. Beaulne works with patients across Ontario to help them understand and manage complex digestive symptoms using a whole-system approach grounded in modern neurogastroenterology.

Frequently Asked Questions

Managing IBS with diarrhea can be challenging, but making the right food choices can help. Here’s what works for many people with IBS:

  • Low FODMAP diet: This dietary approach helps reduce symptoms like diarrhea, bloating, and stomach pain. It involves removing certain foods and gradually reintroducing them to see which ones trigger your symptoms.
  • Easy-to-digest foods: Stick with foods like plain rice, cooked carrots, zucchini, and lean proteins (e.g., chicken, fish) to ease digestion.
  • Avoiding triggers: Steer clear of fatty, spicy, or fried foods, as well as dairy and caffeine. These can worsen symptoms for many people with IBS.

If you’re unsure which foods work for you, consulting with a healthcare provider can help you create a personalized meal plan.

Bloating, gas, and stomach pain are common in IBS. These symptoms often result from:

  • Gas buildup: Undigested food or fermentation in the intestines can cause gas and bloating.
  • Gut motility issues: In IBS, food may move too quickly or slowly through the digestive tract, leading to discomfort.
  • Food sensitivities: Certain foods like high FODMAP foods can cause bloating or pain.

Managing these symptoms typically involves diet modifications, stress management, and finding the foods that work best for your body.

IBS constipation can be tough, but there are ways to improve bowel movements:

  • Increase soluble fiber: Foods like oats, bananas, and carrots can help soften stool.
  • Stay hydrated: Drinking plenty of water helps keep things moving.
  • Exercise regularly: Physical activity helps stimulate digestion.

If these strategies don’t work, gentle laxatives or stool softeners might be considered, but always under the guidance of a healthcare professional.

Certain foods can make IBS symptoms worse, including:

  • High FODMAP foods: These include foods like onions, garlic, certain fruits (e.g., apples, watermelon), and dairy.
  • Fatty foods: Rich, greasy foods often cause discomfort for those with IBS.
  • Caffeine and alcohol: These can irritate the digestive system and increase symptoms like diarrhea or bloating.

By tracking your food intake and symptoms, you can start to identify which foods are causing flare-ups and work toward a personalized plan.

Constant constipation in IBS can be caused by:

  • Low fiber intake
  • Dehydration: Not drinking enough water can make stool hard and difficult to pass.
  • Stress: Emotional stress often affects digestion and can contribute to constipation.

If constipation persists despite lifestyle changes, consider speaking with a healthcare provider for further assessment and potential treatment options.

Severe bloating can occur when:

  • Gas is trapped in the intestines due to difficulty digesting certain foods or fermentation.
  • Slow motility: In IBS, the digestive system may move food too slowly, leading to bloating.

To manage bloating, consider reducing high FODMAP foods and incorporating more digestive-friendly meals. Stress management techniques like yoga or mindfulness can also help reduce bloating by calming the nervous system.