Thirty percent of Americans report that they suffer from food allergies, but according to a new report commissioned by the federal government, the true number hovers around eight percent for children and five percent for adults. That’s a lot of mistaken people.

The data comes from a review of 12,000 studies on food allergies published between 1988 and 2009. Of those, a measely 72 met the criteria of the new report, which included having a big enough sample size and using the right allergy tests.

“Everyone has a different definition” of a food allergy, Dr. Jennifer J. Schneider Chafen, who was the lead author of the new report, told the New York Times. And many of the tests used for diagnosis, especially the skin-prick test and the antibody test, are proving to be somewhat unreliable.

Many of the 30 percent who think they have a food allergy may in fact have an intolerance instead.  Allergies involve the immune system, while many food intolerances are caused by reactions in the digestive tract.