For decades, diet sodas have been marketed as a healthier alternative to their sugar-laden counterparts. Diet root beer, a popular choice among those seeking to reduce their sugar intake, is no exception. But is this bubbly beverage truly a guilt-free pleasure, or does it come with its own set of health concerns? This article delves into the science behind diet root beer, examining its ingredients, potential risks, and offering guidance on how to make informed choices about your consumption.
What's in Diet Root Beer?
Unlike regular root beer, diet versions replace sugar with artificial sweeteners to achieve a sweet taste without the added calories. Diet Coke and Diet Pepsi employ aspartame, an artificial sweetener that imparts sweetness sans calories. Some other diet drinks on the market use different low- or no-cal sweeteners, such as sucralose, saccharin, or stevia. To understand the potential health effects of diet root beer, it's crucial to examine these sweeteners more closely.
Aspartame: A Closer Look
Aspartame is one of the most widely used artificial sweeteners in diet sodas like Diet Coke and Diet Pepsi. It was initially investigated for potential use in an ulcer medication when a scientist discovered its sweetness. The Food and Drug Administration (FDA) has regulated the use of aspartame since 1974 and approved it as a general-purpose sweetener in 1996. The acceptable daily intake for aspartame established by the FDA is 50 milligrams (mg) per kilogram (kg) of body weight per day. A 12-ounce can of diet soda contains about 200 mg of aspartame, so based on these guidelines, a person weighing about 150 pounds (or 68 kg) could drink around 17 cans of diet soda per day.
The Cancer Debate
Researchers and consumers have worried about a possible link between aspartame and cancer for decades as well. In July 2023, the World Health Organization (WHO) reclassified aspartame as “possibly carcinogenic to humans” based on limited evidence. Even so, the WHO still advises that 40 mg/kg of body weight is a safe amount of aspartame to consume per day. The FDA disagrees that the limited evidence points to human cancer risk, citing research that found no link between low- and no-calorie sweeteners and beverages and increased cancer risk in humans. A data-mining analysis published in 2025 determined that artificial sweeteners, including aspartame, might potentially increase the incidence of kidney cancer, low-grade glioma, breast cancer, and prostate cancer. The study’s researchers “strongly advise the public to reduce their intake of artificial sweeteners to alleviate common health issues such as cardiovascular disease, diabetes, and irritable bowel syndrome.” Yet another study published in 2025 found no association between aspartame consumption and invasive breast cancer risk.
Other Potential Health Concerns
Beyond cancer, some research suggests other potential health concerns associated with aspartame consumption. In a review of 29 studies, researchers linked aspartame with neurotoxic effects, such as behavioral concerns, mood disorders, and memory and learning impairments. Older research also associated aspartame with behavioral and cognitive problems - such as headaches, irritable mood, depression, and insomnia.
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Important Considerations
It's important to note that some of the studies occurred in humans, while others took place in animals, so it isn’t entirely clear how those effects would translate to humans. Also, aspartame is not safe for people with the hereditary disorder PKU, which causes phenylalanine to build up in the body. For this reason, people with PKU have to strictly limit their phenylalanine intake and should always choose diet drinks without aspartame.
Other Ingredients of Concern
While aspartame often takes center stage in the diet soda debate, other ingredients can also pose potential health risks.
Caffeine
Diet cola (provided you don’t pick a caffeine-free version) contains about 50 mg of caffeine, says Mangano. That’s about half as much as what you’ll find in a cup of coffee. If you’re sipping several cans of diet cola throughout the day, you could get close to or even exceed the FDA-recommended daily maximum of 400 mg.
Phosphoric Acid
Phosphoric acid is another problematic ingredient, she says. You’ll find it in dark-colored sodas like colas (diet and regular) and root beer, and it’s detrimental to bone tissue. “Research has found that people who had the highest cola intake had the highest rate of osteoporosis,” she says.
Diet Soda and Weight Gain: An Unexpected Twist?
If you’ve heard that diet cola is “bad” for you, you may have also been told that it’s addictive or that it lead to weight gain. Some studies have found that adults with overweight and obesity drink more diet beverages than “normal” weight individuals, but other studies haven’t, says Mangano. Even the studies that suggest obesity and diet soda go hand in hand merely indicate an association, adds Kris Sollid, RD, senior director, nutrition communications for the International Food Information Council (IFIC). Some people have theorized that consuming super-sweet diet drinks makes you crave-and eat-more caloric food, but this hasn’t been proven. No one has quite proven that diet drinks will help you lose weight, either. In fact, May 2023, the WHO issued a guideline advising against the use of non-sugar sweeteners (including but not limited to aspartame) for purposes of weight control.
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Insulin Confusion and Brain Reactions
Diet soda may cause insulin confusion. Your brain normally associates “sweet” with calories. In the realm of human physiology, that’s a good thing. It drives your body to release insulin as sugar’s chaperone to the cells to create fuel. In the past, people assumed this process couldn’t occur when we consumed artificial sweeteners because calories don’t follow the sweet flavor. But one study found the process could very well happen anyway. In the study, individuals who consumed a specific artificial sweetener (sucralose) had increases in both insulin and blood glucose levels. Frequent rises in insulin have been linked to insulin resistance and an increased risk of Type 2 diabetes. Some research also suggests that those who drink diet soda have higher activity in the area of the brain associated with the desire to consume foods high in fat and sugar. Drinking diet soda seems to alter your brain’s sweet-sensing reward center. This means diet soda could potentially change how your brain reacts to cravings for high-calorie foods.
Making Informed Choices
So, is diet root beer bad for your health? The answer, like many things in nutrition, is nuanced.
Moderation is Key
For some people who are trying to control calories, a can of diet cola once a week might be fine. In an ideal world, everyone should probably scrap both diet and regular soda in favor of flavored unsweetened seltzer and other beverages that don’t contain sweeteners of any kind. “A ‘perfect’ diet probably wouldn’t have diet soda in there. But many diets that promote health can include it,” she says. “Not everything has to be organic broccoli and whole grains… It’s really about the totality of your diet.
Consider Alternatives
If you're looking to reduce your diet soda consumption, there are several healthier alternatives to explore:
- Get your caffeine somewhere else. If you crave caffeine (in moderation), you’re likely better off with plain coffee or tea. Just don’t load them up with cream and sugar!
- Add natural flavor to your drinks. If flavor is what made diet soda your drink of choice, try freezing raspberries, cucumber, mint, lemon or lime in ice cubes to add a hint of sweetness.
- Carbonation is key. Many diet soda drinkers relish the carbonation of soda even more than the sweetness. If that’s you, try putting fruit in seltzer or sparkling water to recreate soda’s bubbly appeal. There are also many flavored seltzers and sparkling waters on the market that work well as a diet soda alternative.
- Try new things. There are a lot of alternative beverages out there. Have you tried kombucha? Coconut water? You can even get carbonated apple cider vinegar drinks these days! Just make sure you review the ingredients before you raise a toast to your new, soda-free life.
Lifestyle Changes Can Help
Avoid getting too hungry. Are you the type to skip breakfast? Do you stick to three square meals a day? That’s not setting you up for success because it makes you more likely to crave something sweet during the day. Distract yourself. If you’re suddenly struck with the urge to grab a soda, respond by doing something that isn’t drinking soda. Drink a glass of water: It’s possible you’re just thirsty. Take a 10-minute walk. Call that friend you keep meaning to catch up with. Chances are, that craving’s going to drift to the back of your mind, and eventually disappear. Plan accordingly. Make sure you bring a soda alternative with you to the neighborhood barbecue. Have cold water or iced tea waiting for you in the fridge, so it’s easier to make a healthy choice at the end of a busy day. Anticipating cravings and planning ahead can make confronting them less taxing.
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