Fast food restaurants are usually not the first choice for people who are on a special diet due to food allergies or sensitivities. However, McDonalds may be making its menu a little more friendly for some customers who have to watch what they eat.

McDonald’s British outlets recently tested out a new, gluten-free burger in a week-long trial period that ended October 21. The new menu offering could become a permanent fixture in McDonald’s restaurants.

Gluten is an allergen, found in wheat and a variety of other grains, that causes a number of adverse symptoms in people with celiac disease or a gluten sensitivity. There are a wealth of other people who simply choose not to eat gluten-containing products for health reasons.

Many might be surprised to see the major fast food chain introducing gluten-free burgers when they don’t even offer vegetarian burgers. People who don’t eat meat far outweigh those who avoid gluten in their diet, but there doesn’t appear to be much of a market left for vegetarian options. Sales of meat alternatives have dropped significantly in both the U.S. and Britain since 2008.

While meat-free sales have taken a downward spiral over the years, the demand for gluten-free products is booming. The marketing research firm Mintel reported that gluten-free food and beverage sales have increased $5.4 billion to $8.8 billion in the U.S. in the past two years alone, according to The Economist.

As a result, grocery stores across the U.S. and other wealthy countries are making room for gluten-free products. Restaurants and bakeries, as well, are now offering more gluten-free products than ever before.

“Gluten sensitivity can make enjoying simple, delicious foods difficult. At The Cravory we’ve worked hard to develop a special proprietary gluten-free flour blend so our cookies can still be a treat for those seeking a gluten-free diet,” says Nate Ransom, Co-Owner, The Cravory.

While this is good news for those who need to stick to a gluten-free diet due to allergies, many experts are questioning how long the trend will last. Many view gluten-free foods as another fad diet that has simply reached its peak. These skeptics predict that the gluten-free trend will fade, just as other fad diets have.

It may be a growing trend, but unlike other dietary trends, many people won’t have the choice of going off the diet. More and more people are being diagnosed with celiac disease or gluten sensitivities every day, which could be enough to keep the gluten-free “trend” alive and well.