FODMAPs, explained like a friend would

If you’ve ever been told to “try low FODMAP” and nodded politely while wondering what on earth a FODMAP is, you’re in good company. It’s a mouthful. The idea behind it is simpler.

What are FODMAPs?

Monash University, where the diet was developed, describes FODMAPs as a collection of short-chain carbohydrates (sugars) that aren’t absorbed properly in the gut. Gut bacteria ferment them, producing gas, which can trigger symptoms in people with IBS.

Letter	Group	Monash examples
F	Fermentable	The process: gut bacteria ferment undigested carbs, making gas
O	Oligosaccharides (fructans, GOS)	Wheat, rye, onions, garlic, legumes and pulses
D	Disaccharides (lactose)	Milk, soft cheeses, yogurts
M	Monosaccharides (fructose)	Honey, apples, high fructose corn syrup
P	Polyols (sorbitol, mannitol)	Some fruit and vegetables; artificial sweeteners

Where do these lists fit in the three Monash steps?

Monash describes the low FODMAP diet as three steps, ideally with a dietitian: swap high for low FODMAP foods for 2 to 6 weeks; then reintroduce one FODMAP group at a time; then personalize, eating as widely as you can. These lists are mostly for step 1. Our low FODMAP phases guide explains each step, and the FODMAP challenge log is a printable tracker for step 2.

Easy breakfast swaps

Monash gives a simple example of the swap idea: wheat toast with honey becomes spelt sourdough with jam. More ideas, with the same caution about portions, are in low FODMAP breakfast swaps.

How does the low FODMAP diet work?

Three steps (full detail on our low FODMAP tracker page):

1. Swap high FODMAP foods for low FODMAP ones for 2 to 6 weeks.
2. Challenge one FODMAP group at a time, daily for 3 days, and note your symptoms.
3. Personalize: eat as widely as you comfortably can.

Why not just cut everything out?

Because the goal is the widest diet that keeps you comfortable. Monash’s Step 3 is all about relaxing restrictions, and it suggests re-testing poorly tolerated foods over time, as tolerance can change. Cutting out whole food groups long term without help can make eating harder than it needs to be.

What does the NHS suggest for IBS?

The NHS IBS page suggests keeping a food and symptom diary, and lists foods some people find hard to digest, such as cabbage, broccoli, cauliflower, brussels sprouts, beans and onions, plus avoiding the sweetener sorbitol. These are examples, not a full FODMAP list.

How do I keep track?

A diary is the engine of Step 2. In PoopAI you log each meal by photo or text, tag it FODMAPs, and log your poop with a Bristol type.

Wrap-up

FODMAPs aren’t “bad foods”. They’re foods some guts struggle with. The point of the diet is to find out which ones bother yours, with a dietitian in your corner.

More on this

• The 3 Phases of the Low FODMAP Diet, Explained
• Low FODMAP Breakfast Swaps: Easy Ideas to Start Your Day