FODMAP food guide
Is onion low FODMAP?
FODMAP score
95
High FODMAP
No — Onion is high FODMAP and is a common trigger for IBS symptoms in typical servings.
FODMAPs present
Becomes high FODMAP at
1 tbsp (12 g) or more
Skip onion during elimination — fructans in every form, and powders concentrate them. For reintroduction and beyond, tested low serves DO exist and vary by variety: red onion 10 g on the stricter programme (27 g on the other), sweet/Vidalia 22 g, and yellow/brown 26 g on the second programme, turning high from just 30 g there. Green-topped alliums are the everyday workaround.
Based on published FODMAP research and reviewed reference data. Informational only — not medical advice. Tolerance is individual; verify with a dietitian during the elimination phase.
How much is OK?
This food's verdict depends on the serving. The bands below show where the load builds, group by group.
Fructans
Reintroduction-and-beyond data, not elimination advice. The 10 g figure is the stricter programme’s red-onion serve; sweet/Vidalia tests low to 22 g there, and the other programme passes red onion to 27 g. Variety matters — carry the label.
Bands reflect published FODMAP research for typical preparations — individual tolerance varies, especially mid-reintroduction.
Go deeper
- Why Do Onions Cause Stomach Pain? →
- Reintroducing Fructans: The 3-Day Challenge, Step by Step →
- FODMAP Enzymes, Explained: What Each One Actually Targets →
- Portions: Why the Same Food Can Be Safe and Unsafe →
- Product check: Onion Powder (92/100) →
- Product check: Taco Seasoning Mix (Original packet) (75/100) →
- Product check: Original Ranch Salad Dressing & Seasoning Mix (82/100) →
Related foods — gentlest first
Green scores are the real swaps; matching numbers are just relatives, not alternatives.