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Zero-sugar drinks are replacing diet soda. Are they any better for you?

A dietitian explains.
Bloomberg via Getty Images


Whether for weight loss or to just get healthier, IFIC’s 2021 Annual Food and Health Survey revealed that 40% of people between the ages of 18 and 80 said they were following a prescribed diet in 2021. Yet, at the same time, there’s been a cultural shift away from restrictive dieting, and the word diet itself needs a rebrand. That’s why sodas billed as "diet" are getting overhauled or overtaken by similar (or even the same) zero-sugar soft drinks, according to reporting by CNN . But whether these drinks are any better than the diet drinks they’re replacing is debatable. Here’s how to decide if zero-sugar drinks and sugar substitutes are right for you.

A breakdown of sugar substitutes

Zero- or low-calorie sugar alternatives are often hundreds to thousands of times sweeter than ordinary sugar, but they don’t raise your blood sugar levels. Common sugar substitutes, including sucralose, aspartame, and acesulfame K, are often called artificial sweeteners since they’re made from synthetic ingredients. Meanwhile, others, such as stevia, monk fruit extract, and allulose are naturally derived.

The U.S. Food and Drug Administration (FDA) considers all of these sweeteners safe when consumed in acceptable amounts. The exception is for those with a rare genetic condition called phenylketonuria — aspartame is unsafe for people with this disorder. In determining safety, the FDA reviews data on outcomes such as reproductive health, cancer risk, and potential toxic effects to your nervous system. So, while these additives are considered safe from this point of view, questions remain about whether they raise the risk of other problems and whether they’re helpful.

Related: 15 easy ways to lower the added sugar in your diet

Potential risks of sugar substitutes

While the FDA deems sugar substitutes safe, studies  have linked sucralose with a significant decrease in insulin sensitivity, which is thought to be due to changes in glucose metabolism. This may explain why some research  connects diet soda use with a higher risk of Type 2 diabetes. In one study, researchers tracked more than 66,000 women for 14 years and found that high diet soda drinkers were at a significantly higher risk of developing Type 2 diabetes. Moreover, while diet soda and sugar substitutes don’t raise your blood sugar levels at the moment of consumption, there’s no clear evidence that they’ll help with long-term blood sugar control or weight management, according to the American Diabetes Association.

Meanwhile, studies have also raised concerns that diet soda —including the alternatively-marketed zero-calorie soft drinks — may raise the risk of heart disease and stroke. For example, in one study among more than 81,000 women, high diet soda drinkers (defined as two or more per day) experienced a 23% higher risk of stroke and a 29% higher risk of heart disease compared with low drinkers (less than one per week).

There’s also the potential that sugar substitutes unfavorably influence your gut microbes. More studies are needed to clarify this, but it does raise a red flag given that gut dysbiosis is tied to higher levels of inflammation and metabolic disturbances that may increase the risk of health concerns, like heart disease, cancer, Type 2 diabetes, and obesity.

A more immediate unpleasant effect of consuming sugar alcohols — a type of low-calorie sugar substitute — is gas, bloating and diarrhea. Sugar alcohols, such as sorbitol and mannitol, are often found in lower-sugar candies, protein bars, and gum. Healthy people may experience mild gas or bloating after consuming foods sweetened with sugar alcohols, but if you have a GI condition, like irritable bowel syndrome, or you eat a large quantity of something sweetened with sugar alcohols, you might experience more extreme symptoms.

Do sugar substitutes help you manage your weight?

It makes theoretical sense that replacing a higher calorie food or drink with a lower calorie one would help with weight management. Yet studies aren’t clear. It seems that when you eat or drink something sweet without the calories that you’d typically get from those foods, you may experience changes in your appetite-regulating hormones that make you hungrier and produce stronger cravings. This is a scenario that could promote overeating and weight gain.

One 2021 study examined hunger response and cravings among people who drank a diet drink, a sweetness-matched regular beverage, or water. Researchers found that women and people with obesity were more vulnerable to the appetite-stimulating and cravings-enhancing effects of sugar substitutes. Interestingly, men and healthy-weight individuals didn’t have the same reactions, so it may be that certain populations are more susceptible to the unfavorable effects of these substances.

Who should consider a sugar substitute?

The reality is that most Americans consume too much added sugar, and sodas and other sugary drinks are the leading sources of added sugars in our diets. There are very clear connections between an excessively sugary diet and health problems, including heart disease, so it makes sense to take steps to reduce your added sugar intake.

Alternative sweeteners and zero-sugar sweetened drinks can be part of your plan to reduce added sugars, but don’t get carried away. Just because something has no calories or sugar doesn’t make it healthy or even beneficial in the long run. There’s a chance these substances could be causing metabolic changes that increase — rather than decrease — your risk of obesity and serious diseases.

As part of your sugar step-down plan, try making healthy swaps, like choosing an unsweetened whole grain cereal instead of a sugary one. If a swap is too extreme, you can try mixing an unsweetened food with a sweetened one until your taste buds adapt, and then reduce the amount of the sweetened version you use until you’re using little to none.

If you’re drinking sugar-sweetened drinks, it’s OK to have a diet or zero-sugar alternative instead, but you may want to cut back on these eventually. Ultimately, try to reduce your reliance on sugar substitutes and added sugar.

It’s also helpful to pair your sugar reduction plan with other strategies. When coupled with behaviors, like eating more whole, fiber-filled plant foods, getting adequate sleep, and coping with stress in healthy ways, you should notice that you don’t crave as much sugar and that less sweetened foods taste more enjoyable.