In 2017, low-calorie ice cream juggernaut Halo Top bested Hagen-Dazs and Ben & Jerrys to become the number-one-selling ice cream in the U.S., with more than $324.2 million in sales.

This year, we reached peak Halo when the company opened two scoop shops in LA where fans can get their Halo fix in soft serve form as well as scoops swaddled in a bubbled waffle cone called a puffle.

The appeal of the Instagramable Halo Top and other low-calorie, low-fat ice creams including Breyers Delight , Chilly Cow , Enlightened , Three Twins offshoot Slim Twin , Swell and Sweet Habit is that theyre low in sugar, calories and fat, high in protein and fiber, and theyre all made with some sort of natural sweetener, like the plant-based stevia. Almost all of them contain erythritol, a sugar alcohol used to sweeten the ice cream. Swell contains xylitol, another type of sugar alcohol.

But ... um, what are all those ingredients actually doing to us, aside from being low in calories?

Low-calorie ice creams contain considerably more ingredients than traditional ice creams.

I would consider the fiber, calcium and protein content of these ice creams to be a positive, said Dr. Jessica D. Bihuniak, assistant professor of clinical nutrition at NYU Steinhardt Department of Nutrition and Food Studies and a registered dietician. However, I am not sure these products will satisfy all individuals.

If you look at the nutrition facts, you can see why. Regular ice cream packs a lot more fat and calories.

One serving of Halo Top vanilla bean or half a cup contains:

• 70 calories
• 2 grams of fat
• 6 grams of sugars (5 grams of sugar alcohol)
• 3 grams of fiber
• 5 grams of protein

Even if you eat an entire pint (approximately two cups, or 4 servings), Halo Top clocks in between 280-360 calories, depending on the flavor.

In comparison, just a half-cup serving of Ben & Jerrys vanilla contains:

• 250 calories
• 16 grams of fat
• 20 grams of sugars (no sugar alcohol)
• no dietary fiber
• 4 grams of protein

What accounts for the huge difference in calories? Take a look at the ingredients.

The base ingredients in Halos astounding 25 dairy flavors (and counting) include the following: skim milk, eggs, erythritol, prebiotic fiber, milk protein concentrate, cream, organic cane sugar, vegetable glycerin (a sweetener), natural flavor, sea salt, organic carob gum, organic guar gum and organic stevia leaf extract.

To compare, lets look at the ingredients in Ben & Jerrys vanilla : cream, skim milk, liquid sugar (sugar, water), water, egg yolks, sugar, guar gum, vanilla extract, vanilla beans and carrageenan.

So is that long list of ingredients in Halo Top (and other low-calorie ice creams) actually OK for us to eat?

What do all those ingredients do to our bodies?

We looked at the ingredients in Halo Top, Breyers Delight, Chilly Cow, Enlightened, Slim Twin, Swell and Sweet Habit. Here are some you might wonder about.

Stevia

Stevia is a high-intensity sweetener containing steviol glycosides, used to sweeten foods. Its reported to be 200 to 400 times sweeter than table sugar .

Stevia is categorized as a nonnutritive, meaning it is low- or zero-calorie. The FDA states that stevia leaf and crude stevia extracts are not considered GRAS [Generally Recognized As Safe] and do not have FDA approval for use in food.

Breyers Delights contains a type of steviol glycosides extract named rebaudioside A (Reb A), and Chilly Cow contains the GRAS Reb M extract . Halo Top and Sweet Habit dont specify which kind of stevia leaf extract they use so its hard to say whether theyre GRAS but stevia is listed last on Halos ingredients, and Sweet Habit contains less than 2 percent of the extract.

Bihuniak mentioned that in April, a study published in the journal Obesity pointed to the effect these sweeteners have on rodents and humans.