How the estimate is made
FodCheck reads the ingredient list on a US grocery product and estimates a portion that is likely to stay under published per-serving FODMAP cut-offs. It is an estimate from the label, not a lab test of the jar in your hand.
Cut-offs per serving
From Varney et al., 2017, Table 1 (doi:10.1111/jgh.13698). Oligosaccharides means fructans plus galacto-oligosaccharides.
| FODMAP | Cut-off |
|---|---|
| Oligosaccharides, grains, legumes, nuts, and seeds | 0.30 g |
| Oligosaccharides, other foods | 0.20 g |
| Sorbitol or mannitol, each | 0.20 g |
| Total polyols | 0.40 g |
| Excess fructose | 0.15 g |
| Excess fructose in fresh fruit or vegetables, when it is the only FODMAP | 0.40 g |
| Lactose | 1.00 g |
The paper states polyol cut-offs for sorbitol and mannitol. FodCheck applies the same gram cut-offs to xylitol, maltitol, and isomalt as its own conservative extension, and says so on the estimate.
Ingredient order stands in for amount
Labels list ingredients by weight. FodCheck does not know the true grams, so it spreads the serving across the list with more weight on earlier ingredients. An explicit percent on the label overrides that rank. After a "contains 2% or less of" clause, later ingredients are capped. Wheat is flagged as high only when it looks like a main ingredient. Garlic, onion, and their powders are flagged even when the share looks small. Natural flavors, spices, and seasoning blends stay unclear, because they can hide garlic or onion.
The overall rating is likely low, portion dependent, likely high, or unclear. Where a number is possible, the card says an estimated low portion at about that many grams. Nothing on the site is a certification, and the result is always labeled as an estimate.
Scanning a package
The Scan button calls the camera from your tap, which is what iPhone Safari and Android Chrome require. Chrome on Android can use the built-in barcode detector. Other browsers, including Safari, use a JavaScript decoder for EAN-13 and UPC-A. If you deny the camera, the page tells you and you can type the digits. Add FodCheck to your home screen from the browser menu; the installed icon opens the same site.
Questions
- Is this medical advice?
- General information and estimates only, not medical advice. Talk to a registered dietitian.
- Where do the cut-offs come from?
- Varney J, Barrett J, Scarlata K, Catsos P, Gibson PR, Muir JG. FODMAPs: food composition, defining cutoff values and international application. J Gastroenterol Hepatol. 2017;32(Suppl 1):53–61. FodCheck uses the per-serving cut-offs in Table 1 of that paper. It does not copy laboratory food-composition tables. The grams assigned to each ingredient are FodCheck's own order-of-magnitude assumptions.
- Why is the portion sometimes very small?
- Garlic, onion, inulin, honey, and some sugar alcohols can push a serving over a cut-off even when they sit late in the ingredient list. The estimate rounds down and is labeled as an estimate.
- What does the camera do?
- On your tap, the browser opens the rear camera. Video stays on the phone. FodCheck reads an EAN-13 or UPC-A code and opens that product, or a page where you can suggest a barcode we do not have yet.