Halo Top CEO Justin Woolverton, who created an ice cream with just 240 to 360 calories per pint along with 5 grams of protein, says the dessert counts as a health food because it is low in calories and easy to fit into a balanced diet. Some dietitians have disagreed, cautioning against approaching sweets like ice cream as healthy foods and raising concerns about Halo Top’s use of artificial sweeteners.

“Everybody has their own definition of healthy,” Woolverton told Fortune. “Halo Top is something where people can eat the whole pint or a lot more than a quarter of a cup of ice cream. It can fit into their diet without breaking the calorie bank.”

Halo Top’s playful approach to making ice cream a guilt-free experience has won fans among both dessert lovers and health food enthusiasts since the brand launched in 2012. In 2016, sales of Halo Top’s 17 flavors grew by 2,500% from the previous year, Woolverton says. The company brought in $66.1 million, with more than 13.5 million pints of the ice cream sold at an average price of $4.89.

This week, the company announced that it is now the top seller of ice cream pints in grocery stores, beating mainstay brands like Ben & Jerry’s and Häagen-Dazs. U.S. grocery stores sold more than $31 million worth of Halo Top between June and July, according to sales figures from Halo Top based on data from the market research firm IRI. In the same time period, both Ben & Jerry’s and Haagen Dazs sold about $27 million of ice cream.

To keep calorie levels low in its ice cream, Halo Top cuts out some of the sugar and fat normally found in frozen treats. For the sweet flavor and texture of full-calorie ice cream, Halo Top incorporates the sweetener stevia, a sugar alcohol called erythritol and prebiotic fibers.

Medical professionals have long been skeptical of low-calorie and artificial sweeteners. A recent study found that artificial sweeteners did not help people to lose weight, and were, in fact, linked to weight gain. Though several sugar alcohols are thought to cause digestion issues, erythritol usually has a milder effect, Keri Gans, a registered dietitian in New York City, told TIME

Part of Halo Top’s appeal is that it encourages customers to eat as much ice cream as they want, with messages on pints like “Stop when you get to the bottom.” But some nutritionists say that eating entire pints of ice cream is unhealthy even if the dessert is low in calories.

“No one should eat a whole pint of ice cream,” said Gans. “We should be sitting down to the recommended serving, which is half a cup. If you want to double it, fine, but you shouldn’t sit down to a pint.”

But to Woolverton, the idea of eating only the recommended serving size of ice cream, which is a quarter of a pint, is “flat out unrealistic.”

“People just don’t want to eat like that,” he says.