IBS diet: what to eat, what to avoid, and how low-FODMAP works

How food affects IBS

Irritable bowel syndrome (IBS) is a long-term condition where the gut is more sensitive than usual. It causes abdominal pain with bloating and loose stools, constipation, or both. Food does not cause IBS, but certain foods can trigger symptoms, and stress, poor sleep and irregular meals make the gut more reactive. Our IBS, constipation and abdominal pain guide explains the condition and its tests.

First steps for everyone

Start with these simple changes for four to six weeks before trying a stricter diet.

• Eat three meals at regular times and do not skip breakfast
• Keep a food and symptom diary for two weeks
• Limit tea and coffee to two or three cups a day
• Cut down on fried and very rich food, alcohol and fizzy drinks
• Drink enough water, about eight glasses a day
• Avoid sugar-free sweets and gum with sorbitol, which can cause loose stools

Choosing the right fibre

Soluble fibre, found in oats, isabgol (psyllium husk), ragi and most fruits, helps both constipation and loose stools and is usually well tolerated. Start with one teaspoon of isabgol in water and increase slowly.

Insoluble fibre, such as wheat bran and large amounts of raw salad, can increase bloating and pain in some people with IBS. You do not need to avoid it, but keep portions moderate.

The low-FODMAP diet, in Indian terms

FODMAPs are sugars that some people absorb poorly; gut bacteria ferment them, causing gas, bloating and loose stools. The diet works in three steps: cut high-FODMAP foods for two to six weeks, bring them back one group at a time to see which ones cause symptoms, then return to the widest diet you can tolerate. It is not meant to be followed strictly for life, and works best with guidance.

• Often high in FODMAPs: onion, garlic, rajma, chana, whole moong and other beans, wheat in large amounts, milk, apple, mango, watermelon, cauliflower and mushroom
• Usually lower in FODMAPs: rice, idli and dosa in normal portions, ragi, oats, curd and lactose-free milk, eggs, fish, chicken, paneer, carrot, beans, brinjal, ladies finger, banana (firm), orange, papaya
• Hing (asafoetida) can add flavour when onion and garlic are cut back

When to see a gastroenterologist

IBS is diagnosed after other conditions are ruled out. See a doctor if you notice blood in the stool, black stools, weight loss, anaemia, fever, symptoms that wake you at night, a family history of bowel cancer, coeliac disease or inflammatory bowel disease, or new bowel symptoms after the age of 50.

Dr. Rajasekaran treats IBS and chronic constipation at Healtree Hospital, Neelankarai, ECR, and can arrange blood and stool tests or a colonoscopy at the hospital when needed.