CHICAGO — Plant-based burger orders at quick-service restaurants were up 10% from last year, reaching 228 million servings, according to the NPD Group, Chicago. The market research company said the growth doesn’t necessarily mean meat alternative burgers are closing in on beef burgers or that the growth of meat alternatives corresponds to an increase in vegetarianism or veganism.

Rather, NPD said the strong year-over-year growth of plant-based burgers is primarily due to increased availability at Q.S.R. chains, generating trial on the part of beef burger buyers.

The company’s CREST service, which tracks how U.S. consumers use restaurants, found that beef burgers are still the top sandwich ordered at U.S. restaurants, though growth is flat compared to last year.

The company said that during the year ended April 2019 beef burger buyers made an average of 18 beef burger purchases and 2 plant-based burger purchases.

“Another way to look at it is that 95% of plant-based buyers have made a beef burger purchase within the past year,” NPD said.

Vegans and vegetarians may contribute to plant-based growth, but NPD said they aren’t the primary contributors. A much larger portion of the adult population is looking to increase the amount of plant-based foods in their diet, according to the company’s Health Aspirations and Behavioral Tracker. Concerns about animal welfare and how meat products are brought to the market, sustainability, health and desire to boost protein intake also are fueling the growth in plant-based foods.

“Plant-based burgers allow consumers to substitute without sacrifice,” said Darren Seifer, food and beverage analyst at The NPD Group. “They get the ‘burger’ experience while assuaging their need for more protein and social concerns. With that said, U.S. consumers have not given up on beef burgers but are willing to mix things up every now and then.”