Low-FODMAP Diet for IBS: A Beginner's Guide

The low-FODMAP diet is a short-term plan for irritable bowel syndrome (IBS). You cut high-FODMAP foods such as onion, garlic, wheat in large portions, beans and some fruits for 2 to 6 weeks, then reintroduce them one group at a time to find your triggers. Most people end up avoiding only a few foods, not all of them.

To get a 7-day low-FODMAP meal plan with desi or Western food, try the free low-FODMAP diet plan maker.

What are FODMAPs?

FODMAPs are fermentable carbohydrates that some people don't absorb well. In people with IBS they can draw water into the gut and ferment, causing bloating, pain, gas, diarrhoea or constipation. The diet was developed and tested at Monash University and is recommended by the NHS and other health bodies when first-line advice hasn't helped.

What are the three phases?

1. Elimination (2 to 6 weeks): swap high-FODMAP foods for low-FODMAP ones.
2. Reintroduction (6 to 8 weeks): test one FODMAP group at a time in increasing amounts over a few days, and note symptoms.
3. Personalisation: bring back everything you tolerate and keep limiting only your triggers.

It's best done with a dietitian, especially the reintroduction phase.

Which foods are high in FODMAPs?

• Onion and garlic (including powders), common in curries and tadka
• Wheat, rye and barley in larger amounts: roti, naan, bread, pasta
• Pulses and beans: rajma, chana, many daals in larger portions
• Some fruits: apples, pears, mangoes, watermelon, dried fruit
• Milk and soft cheeses (lactose)
• Sweeteners: honey, high-fructose corn syrup, sorbitol and other "-itols"
• Some vegetables: cauliflower, mushrooms, asparagus

Which foods are low in FODMAPs?

• Grains: rice, oats, quinoa, millet, jowar, bajra, gluten-free bread
• Protein: eggs, chicken, fish, firm tofu, plain meats
• Dairy: lactose-free milk and yogurt, hard cheeses
• Vegetables: carrots, cucumber, tomato, spinach, potato, bhindi, courgette, capsicum
• Fruit: oranges, kiwi, grapes, strawberries, papaya, firm bananas
• Flavour: garlic-infused oil (the FODMAPs don't pass into the oil), the green part of spring onions, ginger, cumin, turmeric, chilli and most dry spices

How do you cook desi food low-FODMAP?

• Make tadka with garlic-infused oil and hing (asafoetida) instead of onion and garlic.
• Use the green tops of spring onions for an onion flavour.
• Small portions of canned, rinsed lentils or moong daal are better tolerated than large bowls of rajma or chana.
• Swap wheat roti for rice or jowar roti during elimination.
• Use lactose-free dahi, or hard cheese instead of paneer in large amounts.

What is a sample low-FODMAP day?

• Breakfast: oats with lactose-free milk, strawberries and a few walnuts
• Mid-morning: an orange or kiwi
• Lunch: rice with chicken curry made with garlic-infused oil, carrot and spinach sabzi, cucumber salad
• Snack: lactose-free yogurt or a few rice crackers with peanut butter
• Dinner: grilled fish with potatoes, courgette and capsicum

Which mistakes should you avoid?

• Staying on the elimination phase for months
• Cutting fibre too much, which can worsen constipation
• Testing several foods at once, so you can't tell which caused symptoms
• Forgetting that portion size matters: many foods are fine in small amounts

When should you see a doctor?

The low-FODMAP diet is for diagnosed IBS. See a doctor before starting if you have blood in your stool, unexplained weight loss, night-time symptoms, anaemia, a family history of bowel cancer or coeliac disease, or symptoms that started after age 50. These need tests first.

How do you reintroduce foods?

Pick one FODMAP group, such as lactose (milk), fructans (wheat or garlic) or GOS (pulses). Eat a small amount on day one, a medium amount on day two and a normal amount on day three, while keeping the rest of your diet low-FODMAP. Wait two or three symptom-free days before testing the next group. Keep notes: your results are personal.

Which other habits help IBS?

Eat regular meals without rushing, chew well, limit caffeine, alcohol and fizzy drinks, and manage stress with walking, yoga or breathing exercises. If constipation is a problem, add soluble fibre such as oats or psyllium gradually and drink enough water.

What should you do next?

For general healthy eating once you've found your triggers, read the healthy diet plan for beginners. Start your elimination week with the low-FODMAP diet plan maker, and track calories and fibre with the food calorie and fibre checker.