Are Shared-Fryer Fries Safe With Celiac? A New Study Found Most Tested Under the Limit
A study of 98 shared-fryer fries and chips found 93.9% under the FDA gluten-free limit. All 6 over it were fries. The authors say it's not a green light.
The question at every restaurant
If you have celiac disease, you know the moment. The fries look great. Then you ask if they share a fryer with the chicken tenders.
The usual advice is a flat no. This study tried to measure what’s actually in the basket.
What the researchers found
The Celiac Disease Foundation led the study with researchers from Children’s Hospital Colorado, Columbia University, Mass General Brigham and others. Samples were collected from September 2025 to January 2026 and tested by Bia Diagnostics, a lab in Vermont, according to the paper.
- Overall: 92 of 98 samples, or 93.9%, tested under 20 ppm. 84 were under 5 ppm, the lowest level the test can measure.
- Chips: all 43 tortilla chip samples were under 5 ppm.
- Fries: all six samples over 20 ppm were fries, about 11% of the fry samples. Those six ranged from 29.6 ppm to more than 80 ppm.
- Oil changes: none of the 39 samples from places that said they change fryer oil daily went over 20 ppm, compared with 4 of 35 from places that said they change it weekly. The other two high samples came from places that didn’t know their schedule.
The study is observational. The daily versus weekly gap was statistically significant, but the foundation says the study “cannot establish that oil-change frequency itself caused the difference.” Oil schedules were also reported by restaurant staff and weren’t checked.
“This study is not a green light to eat from any shared fryer,” said Vanessa Weisbrod, the foundation’s chief programs officer and the study’s lead author. She said the goal is “informed conversations with healthcare providers about risk, frequency of exposure, and individual circumstances.”
Chips came in clean. Fries were the wild card.The WellWham perspective
Our read: chips and fries aren't the same bet
This is our analysis. For years, the shared fryer has been an automatic no. This gives people real numbers to bring to their doctor or dietitian. Chips looked very different from fries in this sample, and the restaurants that said they change oil daily had no high results.
It also shows why “usually fine” isn’t the same as “always fine.” When fries did pick up gluten, some had a lot of it. Three of the six were above 80 ppm, the top of the test’s range.
The reality check
The sample is small. Restaurants weren’t chosen at random, and each one was tested only once, so the study can’t tell you how the same fryer does from day to day. The lead author works at the Celiac Disease Foundation, which ran the study. The paper says it got no outside funding.
The paper also says the 20 ppm limit is a labeling standard, not a personal safety line, and how much you eat and how often both matter. The researchers aren’t recommending that people with celiac disease start eating from shared fryers. Talk to your doctor or a dietitian before changing what you order. For more gluten-free news, see our story on RITZ Gluten Free.
The close
Next time you ask about the fryer, you’ll have a better follow-up question.
How often do you change the oil?
Sources
- Celiac Disease Foundation, October 20, 2026: celiac.org
- Weisbrod et al., Nutrients 18(20):3433, published October 19, 2026: mdpi.com
Brand information: Celiac Disease Foundation
