onion
Vegetables
Is onion high in gos?
Find out whether onion is high or low in gos, see its exact rating, and check its FODMAP, salicylate, oxalate and diet compatibility all in one place.
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Compare onion across criteria
Sensitivity notes
Why gos food checker matters
Galacto-oligosaccharides (GOS) are carbohydrates found mainly in legumes and some vegetables. They're a FODMAP that can ferment in the gut, causing bloating and discomfort in sensitive people.
- Canned and rinsed legumes are lower in GOS than dried
- Start with smaller portions and build up tolerance
- Some people find beano-type enzymes helpful
Triggers
Diets
Serving size, prep, and portion notes for onion
Onion is graded E for fructans and E for total FODMAPs, the top of our scale, which is why it is the single most common trigger people uncover once they start logging food against symptoms. The reaction is a carbohydrate problem rather than an allergy: onion is A for histamine, A for oxalates, A for lectins and A for nightshades, so if onion bloats you the fructans are almost certainly the mechanism. It also grades E for low fermentation SIBO plans. The frustrating part is that fructans are water soluble and heat stable, so caramelizing, slow simmering or fishing the pieces out of a sauce does not make onion any safer, and onion hidden in stock, gravy and spice blends is why so many people react to restaurant food they cannot account for.
Watch for
Fructans and total FODMAPs both graded E, the highest tier we use, and the grade does not soften between raw and cooked onion / Cooking is not a fix: fructans dissolve out of the onion into the pan and stay in the liquid, so straining the pieces out leaves the trigger in the sauce / Hidden onion drives most unexplained flare-ups: stock cubes, gravies, curry pastes, spice rubs, chips and anything listed as seasoning or natural flavor / Graded E for low fermentation SIBO, so onion is usually one of the first things pulled when working through a SIBO protocol / Clean on the rest of the chemistry (histamine A, oxalate A, lectin A, nightshade A, with only a borderline B for histamine liberation), which is why an onion reaction is nearly always intolerance rather than allergy
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GOS Guide
Everything you need to know about gos sensitivity and smart food choices.
Galacto-oligosaccharides (GOS) are carbohydrates found mainly in legumes and some vegetables. They're a FODMAP that can ferment in the gut, causing bloating and discomfort in sensitive people.
Sensitivity varies widely. What triggers one person may be fine for another. Track your reactions to find your personal threshold.
These foods are generally well-tolerated for GOS sensitivity:
View all safe options
These foods have moderate levels and may be tolerated in small amounts:
These foods are high in gos and may trigger symptoms:
View full list
If you're sensitive to GOS, consider these strategies:
- 1Canned and rinsed legumes are lower in GOS than dried
- 2Start with smaller portions and build up tolerance
- 3Some people find beano-type enzymes helpful
- 4Firm tofu is lower in GOS than silken tofu
- 5Sprouted legumes may be better tolerated
Pro tip: Keep a food diary to track your reactions. The Triggerbites app makes this easy with automatic pattern detection.
Want personalized tracking?
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Get the AppFAQ
Is onion high in GOS?
GOS: low signal for most people.
Can I still eat onion if I'm sensitive to GOS?
Usually fine in normal portions.
What else should I check?
Check FODMAPs, Fructans, and Low Fermentation next for a fuller picture.