Most standard ketchup is not low FODMAP. The problem isn’t the tomatoes. It’s the other ingredients that manufacturers add, particularly high fructose corn syrup, onion powder, and garlic powder. All three are high in FODMAPs and show up regularly in popular ketchup brands. The good news is that low FODMAP ketchup options exist, and you can also make your own with simple swaps.
Why Regular Ketchup Causes Problems
Ketchup seems like it should be safe. Tomatoes are low FODMAP at standard serving sizes, and vinegar and salt are fine. But most commercial ketchup recipes include three ingredients that can trigger digestive symptoms in people sensitive to FODMAPs.
High fructose corn syrup is the most common sweetener in US ketchup brands. It contains excess fructose, a monosaccharide FODMAP that many people cannot properly absorb. When fructose isn’t absorbed well in the small intestine, it travels to the large intestine where gut bacteria ferment it, producing gas, bloating, and discomfort.
Onion powder is one of the worst offenders in condiments. Onion is extremely high in fructans, a type of oligosaccharide FODMAP. Even small amounts of onion powder can be enough to push a serving over the safe threshold, because the dehydration process concentrates the fructans.
Garlic powder works the same way. Garlic is also high in fructans, and the powdered form packs those fructans into a very small volume. Many ketchup brands include both onion and garlic powder, which compounds the problem.
How to Find a Safe Ketchup
Your first move is checking the ingredient list. Look for ketchup sweetened with regular sugar (sucrose) instead of high fructose corn syrup, and make sure onion powder, onion extract, garlic powder, and garlic extract are all absent. Some “simply” or “no high fructose corn syrup” varieties meet part of this criteria, but you still need to check for onion and garlic.
The most reliable option is a certified low FODMAP brand. Fody Foods makes a ketchup that carries Monash University’s low FODMAP certification, meaning it has been lab-tested and confirmed to fall within safe FODMAP thresholds per serving. Monash University is the research group that developed the FODMAP diet and maintains the most widely used food database for it. Their certification takes the guesswork out of reading labels.
If you use the Monash FODMAP app, the condiments category was fully reviewed and updated in early 2026 with complete traffic light ratings, so the app’s guidance on ketchup and other sauces reflects current testing.
Regional Differences in Ingredients
Ketchup formulas vary by country. In the United States, high fructose corn syrup is the default sweetener in most major brands. Some other countries use regular cane sugar or beet sugar instead, which changes the FODMAP profile. Sugar (sucrose) breaks down into equal parts glucose and fructose, so it doesn’t create the excess fructose problem that high fructose corn syrup does.
That said, sweetener isn’t the only issue. You still need to check whether onion or garlic powder appears on the label regardless of where the ketchup was made. A sugar-sweetened ketchup that contains onion powder is still high FODMAP.
Making Your Own Low FODMAP Ketchup
Homemade ketchup gives you full control over what goes in. The base is straightforward: tomato paste, vinegar, sugar, and spices. The challenge is replacing the savory depth that onion and garlic normally provide. Several substitutions work well.
- Garlic-infused oil adds garlic flavor without the FODMAPs. Fructans are water-soluble but not fat-soluble, so infusing oil with garlic cloves extracts the taste while leaving the problematic compounds behind.
- Asafoetida is a spice that mimics the savory, slightly sulfurous flavor of onion and garlic. A small pinch goes a long way.
- Green parts of spring onions, leeks, or chives are low FODMAP because the fructans concentrate in the white bulb portion. The green tops add a mild onion-like flavor safely.
- Ginger can add warmth and complexity to round out the flavor profile.
A basic recipe involves simmering tomato paste with vinegar, a bit of sugar, salt, and your chosen flavor substitutes until the mixture reaches the consistency you want. Most homemade versions keep for a couple of weeks in the refrigerator.
Serving Size Still Matters
Even with a low FODMAP ketchup, portion size plays a role. The low FODMAP diet works on thresholds, not absolutes. A food can be safe at one tablespoon and problematic at half a cup. Ketchup is naturally a small-serving condiment, which works in your favor. A typical squeeze on a burger or alongside fries is unlikely to cause issues with a properly formulated low FODMAP version. But if you’re someone who drowns everything in ketchup, the cumulative FODMAP load from tomato paste alone could become relevant at very large amounts.
During the elimination phase of the low FODMAP diet, sticking to a standard serving of one to two tablespoons is the safest approach. Once you move into the reintroduction phase and learn your personal tolerance levels, you may find you can handle larger amounts or even tolerate some regular ketchup brands without symptoms.