FODMAP Portion Calculator
Many foods are safe in small portions but trigger IBS symptoms in larger servings. Use this calculator to find the Monash-approved safe serving size for common foods.
Reviewed by Sarah Mitchell, RDN
Check Portion Safety
Why Portion Sizes Matter on a Low-FODMAP Diet
The low-FODMAP diet isn't just about which foods you eat — it's about how much. FODMAPs accumulate throughout a meal and throughout the day. A food that's perfectly safe at 30g might trigger bloating, gas, or cramping at 100g.
This concept is called FODMAP stacking. Even if each individual food in your meal is within safe limits, eating multiple foods from the same FODMAP group can push you over your personal threshold. Our Portion Calculator helps you stay within Monash-approved limits.
Common Portion Mistakes to Avoid
- Avocado: A whole avocado is high FODMAP. Stick to ⅛ (about 30g) per sitting.
- Canned legumes: Safe at ¼ cup rinsed — not a full can.
- Nuts: 10 almonds is safe, but a whole handful exceeds GOS limits.
- Sweet potato: Half a cup diced is safe, but a whole baked sweet potato is not.