Corn Flakes

Moderate FODMAP

By Michael EisenwasserUpdated October 6, 2026

Serving sizes

Corn Flakes changes rating with portion size. These are the amounts tested in the literature behind our ratings.

About 25g Low
Larger portions Moderate
Much larger portions High

Fructans

Corn flakes are Moderate FODMAP at a usual bowl, though about 25g is low.

Corn flakes are low at about 25g.
Fructans build as the bowl grows, so larger portions are moderate and much larger portions are high.
Cereal is easy to over-pour, so bowl size really matters here.

Measure out about 25g rather than free-pouring, and rotate in oat or rice-based cereals.

Why corn flakes is rated moderate

Corn flakes are moderate at an ordinary bowl and low only at about 25g, which is a small bowl by most people's pour. Larger portions are moderate and much larger portions are high. Fructans are what drives that climb, and the gap between the rungs is not generous. It helps to remember what a flake is: a dried, toasted cereal with the water driven out, so a light looking bowl holds a lot of grain by weight, in a way a bowl of anything fresh does not. Moderate is the rating to respect rather than relax about, because a cereal you pour rather than measure is one of the easiest things in the kitchen to overshoot before the day has even started.

What changes your risk

The pour this is the whole game. About 25g is low, larger portions are moderate and much larger portions are high, and a free poured bowl closes that gap quickly. A weighed pour into a smaller bowl is the difference between the rungs.
Drying and flaking concentrate it fresh corn has not had its water driven off, a flake has. That processing is why a modest looking volume of cereal carries the load it does, and it is why cereal servings look so much smaller than people expect.
Stacking at breakfast corn flakes reach moderate on their own at an ordinary bowl, so they are the food most likely to tip a meal over. Wheat toast on the side, a second wheat based cereal, or rye bread within the same few hours all add fructans to the same total.
What goes on top dried fruit concentrates everything left behind after the water goes, and honey and agave syrup are poor additions here. Maple syrup, strawberries, blueberries, raspberries, a firm just yellow banana, walnuts, pecans or pumpkin seeds are better company, with lactose free milk in the bowl.
The ingredient list cereals in this aisle often carry malt or wheat ingredients, and some carry added inulin or chicory root fibre, which belongs nowhere near a bowl you are already keeping an eye on. Read the list before the box goes in the trolley.

Swaps

For a breakfast bowl that is not working against you, rolled oats as porridge or overnight oats, a plain puffed rice cereal, quinoa flakes and polenta porridge all fill the same role, with lactose free milk and a low FODMAP fruit on top. Plain rice cakes with peanut butter or a hard cheese do the quick crunchy breakfast job too. What does not substitute: cereals built on wheat or bran, muesli and granola carrying dried fruit, and anything listing inulin or chicory root fibre, since those are the same fructan problem in a different box.

How to lower the load

Keep a kitchen scale or a marked cup in the cereal cupboard and use it every time, because the size of the bowl decides the size of the pour more than hunger does. A smaller bowl makes about 25g look like a proper breakfast instead of a sad one. Serve, put the box away, and skip the habit of topping up to finish the milk, which is usually what carries a bowl from moderate to high. If breakfast is a buffet or a hotel spread, portion into a bowl at the table rather than filling from the dispenser. Adding protein alongside, such as eggs or a hard cheese, makes the portioned bowl hold better than a bigger bowl of flakes on its own.

Common questions

how much corn flakes is low fodmap

About 25g is low. Larger portions are moderate and much larger portions are high, so a freely poured bowl usually lands at moderate or above.

are corn flakes high in fructans

Fructans are the group driving the rating. At about 25g the fructan load is low, at larger portions it is moderate, and at much larger portions it is high.

can i eat corn flakes on the elimination phase

Corn flakes are moderate at an ordinary bowl and low only at about 25g, so they fit the elimination phase only as a small, weighed bowl. Rolled oats or a plain puffed rice cereal cover the same breakfast with more room. Reintroduction is planned with a dietitian.

are corn flakes the same as fresh corn

No. Flaked cereal has had its water driven off, which concentrates what is left, so a small volume of flakes carries far more grain than the fresh form it looks related to.

Learn more

Where this rating comes from

Corn Flakes is rated from published lab measurements of its FODMAP content, using the low, moderate and high cutoffs of Varney et al. (2017).

Feedback sent through the FODMAP Foods app has led to changes in this list.

See our full rating method →

Sources

Fructan and free fructose content of common Australian vegetables and fruit. Muir et al. (2007), J. Agricultural and Food Chemistry 55(16):6619-6627.
Measurement of short-chain carbohydrates in common Australian vegetables and fruits by high-performance liquid chromatography (HPLC). Muir et al. (2009), J. Agricultural and Food Chemistry 57(2):554-565.
Quantification of fructans, galacto-oligosaccharides and other short-chain carbohydrates in processed grains and cereals. Biesiekierski et al. (2011), J. Human Nutrition and Dietetics 24(2):154-176.
Dietary sorbitol and mannitol: food content and distinct absorption patterns between healthy individuals and patients with irritable bowel syndrome. Yao et al. (2014), J. Human Nutrition and Dietetics 27(Suppl 2):263-275.
FODMAPs: food composition, defining cutoff values and international application. Varney et al. (2017), J. Gastroenterology and Hepatology 32(Suppl 1):53-61. Supplies the low, moderate and high cutoffs used on this page.