Eating at Burger King with celiac disease, IBS or food allergies

It depends on what you need to avoid. As of October 2026, Burger King’s US Nutrition Explorer shows an allergen line for each menu item. Most items list what they contain, and many also list what they may contain and what they may contain via shared equipment. That third line is Burger King’s own cross-contact warning, and it’s worth reading as closely as the first.

Burger King’s explorer, when we checked, didn’t describe any US item as gluten-free or allergen-free. So this guide doesn’t point to "gluten-free" or "allergy-friendly" choices. Instead, it summarizes what Burger King’s own pages list, so you can see where wheat, milk, egg, sesame, fish and common FODMAP sources show up, and what to ask.

When you open an item in Burger King’s Nutrition Explorer, the allergen section can show up to three lines. They mean different things, and all three matter if you have an allergy or celiac disease:

• Contains: the allergen is an ingredient. For example, the Whopper lists eggs, soy, wheat and sesame.
• May contain: the allergen may be present even though it isn’t a listed ingredient. Several Croissan’wich and biscuit sandwiches show "May contain: Sesame".
• May contain via shared equipment: the item may pick up the allergen from equipment it shares with other foods. The fries show wheat here, the Game Day Pretzel Burger shows sesame, and the vanilla, chocolate and strawberry shakes show soy and wheat.

It can be tempting to read only the first line. But FARE notes that even a tiny amount of a food protein has caused reactions in people with food allergies, and that cooking does not remove an allergen. If an allergen you react to appears on any of the three lines, treat the item with the same caution as if it were an ingredient, and talk to your allergist about what level of risk is acceptable for you.

A missing line isn’t a promise either. An item with no shared-equipment line still comes out of a shared kitchen, so tell staff about your needs every time.

As of October 2026, Burger King lists its French fries ingredients as potatoes, vegetable oil, modified potato starch, rice flour, salt, leavening, dextrose and xanthan gum, cooked in vegetable oil. There’s no wheat ingredient, but the allergen line reads "May contain via shared equipment: Wheat".

Other fried sides are listed differently. Onion rings and Have-sies are listed as containing wheat, with possible milk, fish and soy via shared equipment. Chicken nuggets list wheat, with possible milk, fish and soy via shared equipment. The Celiac Disease Foundation lists fried foods cooked in oil shared with breaded products as a cross-contact risk, which is consistent with what Burger King’s own labels suggest.

If you have a fish allergy, notice how often "fish" appears in the shared-equipment line: on the crispy and original chicken sandwiches, nuggets, chicken fries, onion rings and several breakfast sandwiches when we checked. Ask your restaurant how its fryers are used.

These are examples from Burger King’s US Nutrition Explorer when we checked it in October 2026. They describe what Burger King lists. They are not recommendations, and they can change.

The Whopper’s ingredient list breaks it into components. The sesame seed bun lists wheat flour, malted barley flour, sesame seeds, soy flour and wheat gluten. The mayonnaise lists eggs and dried garlic, and the ketchup lists onion powder. The beef patty is listed as 100% beef with a salt and pepper seasoning. The Impossible Whopper still lists eggs, so check plant-based items as carefully as any other. Adding cheese changes the allergen line too: the Whopper with Cheese adds milk, and every Texas Whopper lists milk. If you add or swap anything, check the allergen line for each component you add, not just the standard item.

You can ask for the bun, cheese or mayonnaise to be left off. But FARE explains that peeling cheese off a cheeseburger is direct cross-contact, and that a spatula used for a cheeseburger can carry milk to a hamburger. If you have an allergy or celiac disease, ask for the item to be made without the component from the start, and ask about shared utensils. Our guide to burgers and fast food with food restrictions covers this in more detail.

For milk allergy and lactose intolerance, notice that some items without milk in the "contains" line still list it via shared equipment, such as the nuggets and Chicken Jr. For sesame, many sandwich buns list it as an ingredient, and several breakfast items list "may contain: sesame".

Monash University lists onion, garlic, wheat bread, cow’s milk and ice cream among higher-FODMAP foods, and potato and lettuce among lower-FODMAP ones. Based on Burger King’s US information as of October 2026:

• Onion: onions and onion powder in the ketchup on the Whopper; onion rings.
• Garlic: dried garlic in the Whopper mayonnaise.
• Wheat and barley: wheat in buns, biscuits, croissants, breaded chicken, onion rings and cones; malted barley flour in the Whopper bun. Barley isn’t one of the nine labeled allergens, so read full ingredient lists.
• Lactose: in cheese, shakes and soft serve.

Asking for no onion and sauces on the side is a simple starting point for IBS. Portion matters with FODMAPs, so a smaller sandwich or side may sit differently from a large one.

For celiac disease, the fries’ shared-equipment wheat note and the shared kitchen matter as much as the ingredients. Whether that level of risk works for you is a decision to make with your gastroenterologist or dietitian. Our guides to eating out with celiac disease, hidden garlic and onion and eating out with IBS have more ideas.

1. Look up the item first in Burger King’s US Nutrition Explorer or app, and open the item to see its ingredients and all three allergen lines.
2. Check every component, including sauces, cheese and the bun.
3. Order without the component from the start, rather than removing it later.
4. Tell staff about an allergy or celiac disease when you order, even if you use the app or a kiosk. Ask about shared utensils, broilers and fryers.
5. Check your order when it arrives. If something you asked to leave off is there and you have an allergy or celiac disease, ask for a fresh one.
6. If you’re unsure, skip it. It’s fine to choose something simpler, or eat elsewhere.

Phrases you could use:

• "I have a fish allergy. Are the fries or chicken cooked in the same oil as the fish?"
• "I have a milk allergy. Could you make this without cheese from the start, and change gloves?"
• "I have a sesame allergy. Is there a bun without sesame, and is it stored separately?"
• "Could I have it with no onion and no mayo, with ketchup on the side?"

For more on explaining your needs, see talking to restaurant staff about allergies. If you’re comparing chains, our McDonald’s guide covers the same questions.