Onion
Rating: high FODMAP · Trigger subgroup: Fructans
At a 10 g portion: amber light
Lights per subgroup
- Fructans 0.2 g · amber light
- GOS 0.02 g · amber light
- Excess fructose 0 g · green light
- Lactose 0 g · green light
- Sorbitol 0 g · green light
- Mannitol 0 g · green light
fructans and GOS are evaluated together (oligosaccharide sum) · sorbitol and mannitol are evaluated individually and combined — the worse result wins
Green boundaries come from the scientific sources; the amber (1–2× the cutoff) and red (>2×) bands are an app estimate.
Sources and confidence
- Method:
- subgroup grams from peer-reviewed literature
- Rating confidence:
- high
- Assessed:
- 2026-08-23
- Portion thresholds:
- varney-2017.v1
Sources
- doi:10.3389/fnut.2024.1446771 — onion fructan 1.97 g/100g fresh; consistent with Varney 2017 Table 2 ≈1.8 and JM2014 total FOS 2.01
- doi:10.1080/10942912.2012.680221 — Jovanovic-Malinovska 2014 Table 4: white onion raffinose 0.23 ± 0.011 g/100g fw, stachyose nd; Table 2: sorbitol nd, mannitol nd
- doi:10.1111/jgh.13698 — Varney 2017 Table 2: onion 36 g serve GOS 0.07 ≈ 0.19/100g, sorbitol nd, mannitol nd — GOS 0.23 = the higher measured point, worse light wins
- USDA FDC 170000 — glucose 1.97 > fructose 1.29 — no excess
Hollow circle = no data (unknown). Hatched = medium/low confidence. Solid = high confidence.
Test your tolerance in the protocol
Fodo walks you through a Fructans tolerance test — and the rest of the 3-phase FODMAP protocol.