Standard Heinz Tomato Ketchup contains onion powder and high fructose corn syrup, both of which are FODMAP triggers. That said, ketchup is used in such small amounts that a single serving (about one tablespoon or 13 grams) is generally considered low FODMAP. The answer depends on how much you use and which version of Heinz you’re buying.
Why the Ingredients Look Concerning
The U.S. formulation of Heinz Tomato Ketchup lists these ingredients in order: tomato concentrate, distilled vinegar, high fructose corn syrup, corn syrup, salt, spice, onion powder, and natural flavoring. Two of those stand out for anyone following a low FODMAP diet.
Onion powder is a concentrated source of fructans, one of the main FODMAP groups. Monash University, the research institution behind the low FODMAP diet, specifically warns that onion and garlic in powder form contribute significantly to a food’s FODMAP load, even in small quantities. This makes onion powder different from most ingredients where trace amounts are a non-issue.
High fructose corn syrup (HFCS) raises the ratio of fructose to glucose in a food. When fructose exceeds glucose, the excess fructose becomes a FODMAP because it’s poorly absorbed on its own. HFCS tips that balance in the wrong direction. The “natural flavoring” and “spice” entries on the label are also unknowns, since manufacturers aren’t required to disclose what’s in proprietary blends.
Why a Small Serving Is Still Considered Safe
Despite those ingredients, a 13-gram serving of ketchup (roughly one tablespoon) tests as low FODMAP. Onion powder sits near the very bottom of the ingredient list, meaning it makes up a tiny fraction of each squeeze. At that serving size, the total fructan and fructose load stays below the threshold that triggers symptoms for most people.
Interestingly, the tested low FODMAP serving size is the same whether the ketchup contains HFCS or plain sugar: 13 grams either way. So the sweetener type matters less than the portion. The trouble starts when you use ketchup generously, dipping fries repeatedly or spreading it thick on a burger. Two or three tablespoons can push both the fructan and fructose content into moderate or high territory.
U.S. vs. European Formulations
If you’re outside the United States, your Heinz Ketchup likely has a different recipe. European versions use cane sugar instead of high fructose corn syrup, which eliminates the excess-fructose concern. Cane sugar (sucrose) breaks down into equal parts fructose and glucose, so there’s no fructose surplus to cause trouble.
The European formulation still contains onion powder and natural flavoring, so it’s not completely free of FODMAP ingredients. But removing HFCS does take one variable off the table. At a single-tablespoon serving, the European version is a slightly better bet on paper, though the practical difference at that small portion is minimal.
Heinz Simply Tomato Ketchup
Heinz sells a “Simply Tomato” version with a shorter ingredient list: tomato concentrate, distilled vinegar, cane sugar, salt, onion powder, spice, and natural flavoring. Swapping cane sugar for HFCS is an improvement for the same reason the European formula is preferable. But onion powder is still present, and it actually appears higher on this ingredient list than on the original, which could mean a slightly larger proportion.
Simply Tomato is a reasonable choice if you want to avoid HFCS, but it’s not a FODMAP-free product. The same one-tablespoon limit applies.
Certified Low FODMAP Alternatives
If you’d rather not worry about portion math, FODY Foods makes a tomato ketchup that carries official Monash University low FODMAP certification. It’s formulated without onion, garlic, or high fructose corn syrup, so the ingredient list is clean from a FODMAP perspective. You’ll pay more for it, but the tradeoff is peace of mind during the elimination phase when precision matters most.
FODY is the only ketchup brand with formal Monash certification as of mid-2025. Other brands may market themselves as “FODMAP friendly” based on their ingredient lists, but without third-party testing, there’s no guarantee the final product falls below FODMAP thresholds.
Practical Tips for Using Heinz Ketchup
If you want to keep Heinz in your fridge during the elimination phase, stick to one level tablespoon per sitting. Measure it once or twice so you know what that looks like on your plate, then eyeball it going forward. Avoid stacking other FODMAP sources in the same meal, since the small fructan contribution from ketchup could combine with fructans from bread, pasta sauce, or other condiments to push you over your personal tolerance.
During the reintroduction phase, you’ll have a clearer picture of your fructan sensitivity. Some people tolerate onion powder in trace amounts with no issues, while others react to even small exposures. If fructans turn out to be your main trigger, switching to the FODY version or making a simple homemade ketchup from tomato paste, vinegar, sugar, and salt gives you full control over what goes in.