Cornflakes
Grains · Breakfast Cereals
Plain cornflakes are rated green at a cup, 30 g, on 0.02 g of fructans and nothing else at all. That makes them quietly unusual, because the breakfast aisle is where inulin, chicory root fibre, dried fruit and honey do most of their hiding. The oldest and least interesting box on the shelf turns out to be the one with the shortest ingredients list.
Last updated 4 September 2026Serving sizes for cornflakes
A cup of flakes, 30 g, is the tested serve and it rates green.
Tested serving sizes
| Serving | Amount | Main FODMAP | Rating |
|---|---|---|---|
| 1 cup | 30 g | Fructans 0.02 g |
Breakdown for 1 cup
Is cornflakes low FODMAP?
Corn is a low-fructan grain to start with, and cornflakes are made from degermed grits that are cooked, rolled and toasted, so the ingredients rarely run past corn, sugar, salt and malt flavouring. The tested cup comes back at 0.02 g of fructans, a fifth of the 0.1 g line where the group begins to count as moderate, and empty across the other five. Very little goes into the box, which leaves very little for bacteria to work on further down.
Cornflakes and IBS: what to know
This page matters because of the boxes either side of it. Bran and wheat cereals bring fructans from the grain itself, granola is rated amber at two tablespoons, and anything marketed on added fibre may well be built on inulin, which is concentrated fructans put in on purpose. Dried fruit is the other one: a small handful of raisins, 40 g, is rated red, and a fruit-and-nut cereal can carry that much without looking like it does. Read the fruit line, the fibre line and the sweetener line before you read the front of the packet.
Gut-friendly ways to eat cornflakes
The milk decides this bowl. Lactose-free milk is rated green at a full cup and pours like dairy because it is dairy, while almond and rice milks both work and simply taste thinner on flakes. Oat milk is rated green at half a cup and amber at a whole one, which is worth knowing when cereal takes more milk than coffee does. Regular milk is rated red at a cup, and that is the usual way a green breakfast stops being one. Sliced strawberries or a third of a ripe banana finish it without adding much.
Frequently asked questions
Are cornflakes OK for IBS?
For most people at this portion, yes. A cup rates green on a trace of fructans, which is about as clean as a packaged breakfast gets. What ruins a cornflake breakfast is nearly always poured on afterwards: regular milk, a spoon of honey, a whole banana past its green serve, or a scattering of sultanas. Sort the toppings out and the cereal itself asks very little of you.
Which breakfast cereals are low FODMAP?
Plain corn, rice and oat-based cereals are the dependable end of the aisle, with the caveat that oats carry a portion limit of their own: half a cup dry of oats is rated green and a full dry cup is rated red. The ones to approach carefully are wheat and bran cereals, muesli, granola, and anything advertising added fibre, which normally means chicory root.
Can I put honey on my cornflakes?
Not if you want the bowl to stay green. Honey is rated red at a single teaspoon on excess fructose alone, making it one of the few toppings that can outweigh everything else in front of you. Maple syrup is rated green and does the same job on flakes, and plain table sugar is not a FODMAP at all.
How big is a serve of cornflakes?
A cup, 30 g, is what has been measured, and flakes are light enough that a cup fills less of a bowl than you would expect. No larger pour has been tested, though with fructans this low there is not much room for a big number to appear. Weigh one bowl once and you will know whether your usual habit is one serve or nearer three.
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