Oat milk is everywhere — in flat whites, on cereal, in smoothies. But if you're managing IBS or following a low FODMAP diet, the obvious question is: is oat milk actually low FODMAP? The short answer is yes, in the right portion — but there are a couple of important caveats worth knowing.
The short answer
Oat milk is low FODMAP in modest servings. The fermentable carbohydrates in oats are dose-dependent, so a splash in your coffee or a small glass is usually fine, while large quantities can tip you over your personal threshold. Portion is everything — the Monash University FODMAP app lists current low FODMAP serving sizes and is the most reliable place to check.
Watch out for added fibres
The bigger issue is often what's added to commercial oat milk. Some brands include inulin, chicory root or added "fibre" to play up a gut-health angle — and these are high FODMAP fructans that commonly trigger bloating in people with IBS. Always read the ingredients list and skip oat milks containing inulin or chicory root if you're sensitive.
How to choose a gut-friendly oat milk
- Pick a plain, unsweetened oat milk with a short ingredients list.
- Avoid added inulin, chicory root fibre or FOS.
- Keep servings moderate, especially during the elimination phase.
- If oat milk doesn't agree with you, almond milk is low FODMAP in a 250ml serving and works just as well.
Oat milk and protein — a gut-friendly match
Oat milk's mild, naturally sweet flavour makes it ideal for protein shakes and porridge. Blended with a certified low FODMAP protein like Blissful Brown Rice & Raw Cacao — FODMAP Friendly certified and made from just organic brown rice protein and organic raw cacao — it makes a simple, IBS-friendly shake with no dairy, lactose or hidden triggers. It works beautifully in our oat-based porridges too.
The bottom line
Yes, oat milk can absolutely be part of a low FODMAP diet — just keep portions moderate and steer clear of versions with added inulin or chicory root. For more, see our beginner's guide to the low FODMAP diet and our low FODMAP shopping list.
Browse the full range at thatprotein.com — free UK delivery on orders over £30.
This article is for general information and isn't medical advice. If you have IBS or any digestive condition, please consult your GP or a registered dietitian.