Is Stevia Safe?

By: Laurie S. Herr

It sounds sweet: a natural, no-calorie sweetener that doesn't raise blood sugar. Just how safe is stevia, and can it help you lose weight? What about side effects? Experts don't have all the answers yet, but here's what they know so far.

Photo: Bima Ramadhani/EyeEm/Getty Images

News flash: Most of us eat w-a-a-a-y too much added sugar—around 17 teaspoons a day, according to the U.S. Department of Agriculture. That's nearly three times more than the limit the American Heart Association recommends of 6 teaspoons a day for women (and around 9 teaspoons for men). All that sweet stuff not only packs on pounds but also can hike up your risk for heart disease, diabetes and other chronic diseases.

Many people see a sweet solution in stevia, a no-calorie sweetener often used in sodas, candy, baked goods, jams, jellies and umpteen other foods labeled "sugar-free" or "diet." Just how safe is it? Does it have side effects? Here's what experts know so far.

Related: 6 Swaps to Slash Added Sugars from Your Diet

What is stevia?

Stevia is a liquid or powdered sweetener sold in the U.S. under several brand names, including Truvia, Stevia in the Raw and others. It's made from a South American plant called stevia, the leaves of which are 200 to 400 times sweeter than regular table sugar. People in South America have used the stevia plant for hundreds of years, both as a sweetener and as a remedy for burns, stomach troubles and other problems.

While the stevia you buy at the grocery store is technically plant-based, in reality it's a highly processed extract that's often combined with other ingredients. Some brands, like Truvia, contain sugar alcohols, a type of low-calorie carbohydrate.

Related: A Buyer's Guide to Sugar Substitutes

Is stevia FDA-approved?

Stevia has an FDA rating known as Generally Recognized as Safe (GRAS). Sweeteners and other food ingredients with GRAS status don't require FDA approval and can be legally added to foods sold in the U.S. The GRAS rating does not apply to whole-leaf stevia and less-processed stevia extracts, which cannot legally be added to food products in the U.S.

What are the health benefits?

You get a natural sweetener with zero calories that doesn't affect blood sugar—a plus for people with diabetes. Along with other sugar substitutes, stevia is also linked to fewer cavities. And it gets a good report card from some public advocacy groups: a 2014 report by the Center for Science in the Public Interest listed stevia as one the safest sugar substitutes.

Related: The Truth About Sugar

Are there any downsides?

For starters, there's the taste. Stevia has a slightly bitter flavor that some people don't like. Stevia products made with sugar alcohols can also cause bloating, diarrhea and other stomach troubles for some people.

And there are other possible problems. Some research suggests stevia could make you gain weight. A 2017 review published in the Canadian Medical Association Journal looked at nearly 40 observational studies that followed people for periods ranging from six months to 10 years. The review found that people who regularly used stevia and other non-nutritive sweeteners had some weight gain, along with a higher average BMI and a higher risk of diabetes, high blood pressure, metabolic syndrome and heart disease.

Other research suggests stevia may interfere with the growth of certain probiotic bacteria, which are important for a healthy gut.

Finally, keep in mind that some studies promoting stevia are funded by food companies, so it's wise to take the results with a grain of salt.

Related: How to Cut Back on Sneaky Added Sugars

Can I eat too much of it?

It would be pretty difficult. The World Health Organization defines the acceptable daily intake (ADI) as 4 mg of stevia per kilogram of body weight. According to an FDA estimate, that means a 150-pound person could safely eat up to 10 packets of stevia a day—way more than you actually need, considering its intense sweetness.

That said, you should stop using stevia if you have any nausea, bloating or other side effects.

Can I use stevia in recipes?

It depends. Estimating equivalent amounts to replace sugar can be tricky—not only because stevia formulas vary among brands, but because the sweetness is so highly concentrated. According to stevia.com, 1 tablespoon of sugar can be generally be replaced by 1 to 1½ teaspoons of a stevia baking blend. Your best bet: check the label of the stevia brand you choose and follow its directions for replacing sugar in cooking and baking. Stevia can also affect the texture of a recipe, so you may need to experiment.

Related: Healthy Snacks to Satisfy Your Sweet Tooth

What's the bottom line?

Most experts agree that more studies are needed on stevia's long-term effects, particularly when it comes to weight gain and diabetes. Still, commercial stevia sweeteners sold in the U.S. appear to be a safe sugar substitute.

Just don't think of stevia as a sure ticket for weight loss. Instead, some experts suggest incorporating stevia into your diet—maybe a pinch in your morning coffee or mixed into a smoothie—as a way to cut back on added sugars overall. That's the real goal.

Related: 3 Ways to Break Your Sugar Habit

Watch: What a No-Sugar Day Looks Like