Cornstarch is a common thickener used in sauces, soups, custards, and gluten-free baking — but if you’re following a Low FODMAP diet, you may wonder:
Is cornstarch low FODMAP?
The short, evidence-based answer is: Yes, cornstarch is considered low FODMAP in normal serving sizes.
Here’s the full scientific explanation and everything you need to know.
✔️ Quick Answer: Yes, Cornstarch Is Low FODMAP
According to data from Monash University — the leading research institution behind the Low FODMAP diet — cornstarch (also called cornflour) contains negligible fermentable carbohydrates, meaning it does not trigger symptoms for most people with IBS.
This makes cornstarch a safe ingredient during the elimination phase of the diet.
Why Cornstarch Is Low FODMAP: The Science
1. Cornstarch Is Almost Pure Starch
Cornstarch is produced by isolating the endosperm of the corn kernel and refining it until you’re left with:
- ≈ 90–100% starch
- Almost no sugars
- No fiber
- No polyols
- No oligosaccharides
Because FODMAPs are fermentable carbohydrates, a nearly pure starch product contains none of the compounds that typically cause digestive symptoms.
2. Starch Is Not a FODMAP
FODMAPs include specific carbohydrate groups:
- Fructose
- Lactose
- Fructans
- GOS
- Polyols
Starch is not on this list, and the digestive system handles starch differently:
- Starch is broken down by enzymes (amylase) in the small intestine
- It does not reach the large intestine in significant amounts
- Therefore, it does not ferment or cause IBS-related symptoms
3. Research Confirms Its Low FODMAP Status
Monash University has officially tested cornstarch and classified it as:
- Green (safe)
- Low FODMAP
- Safe in standard culinary portions (1 tbsp / 8–10 g)
Larger servings do not change its FODMAP rating, because the ingredient contains no fermentable carbohydrates.
How Much Cornstarch Is Safe?
Recommended low FODMAP serving:
➡️ 1 tablespoon (≈ 8–10 g) — officially confirmed low FODMAP.
Most recipes for thickening require only:
- 1–2 tbsp per dish
- Shared across multiple servings
This means you’re rarely consuming more than 1 teaspoon personally — well within the safe range.
Is Corn Flour the Same as Cornstarch? (Important for FODMAPs)
This causes confusion depending on country:
| Term | US/Canada | UK/Australia | FODMAP Status |
|---|---|---|---|
| Cornstarch | Pure starch | Cornflour | Low FODMAP |
| Corn flour | Finely ground whole corn | Can mean cornstarch | Varies |
| Masa harina | Lime-treated corn flour | Same | Low FODMAP in small amounts |
✔️ If the product is pure starch, it’s low FODMAP.
❌ If it is whole-grain corn flour, it may contain fiber & fructans — raising FODMAP content.
Is Cornstarch Safe for IBS?
Yes. Because cornstarch is:
- Easily digested
- Low residue
- Non-fermentable
- Gluten-free
…it is very unlikely to cause IBS symptoms.
Many IBS-friendly, low FODMAP recipes (gravies, custards, gluten-free baking mixes) rely on cornstarch for this reason.
Low FODMAP Uses of Cornstarch
Use cornstarch safely in:
✔️ Thickening sauces and gravies
It replaces flour (which may contain FODMAPs like fructans).
✔️ Baking (especially gluten-free)
Cornstarch adds structure without triggering symptoms.
✔️ Coating meats & vegetables
Ideal for low-FODMAP crispy frying.
✔️ Custards, puddings, pie fillings
Pure starch = low FODMAP.
When Cornstarch Might Cause Symptoms (Non-FODMAP Reasons)
Even though cornstarch is low FODMAP, some people may still react due to:
- Corn allergy (rare)
- Large amounts causing rapid digestion
- Ingredients mixed with cornstarch (e.g., seasoning blends, gravies)
Always check labels for:
❌ Onion powder (high FODMAP)
❌ Garlic powder
❌ High-fructose corn syrup
❌ Wheat fillers
Pure cornstarch itself remains safe.
Conclusion: Is Cornstarch Low FODMAP?
✔️ Yes — Cornstarch Is 100% Low FODMAP.
It contains almost pure starch, no fermentable carbohydrates, and is officially classified as low FODMAP by Monash University.
This makes cornstarch a safe and versatile ingredient for anyone following:
- The Low FODMAP diet
- An IBS-friendly lifestyle
- A gluten-free diet
You can confidently use it in cooking, baking, and thickening recipes without worrying about triggering symptoms.