Since their introduction in the 1950s, diet sodas have been marketed as a healthier alternative to regular sodas. However, the true health implications of diet soda have recently come under scrutiny. This article explores the differences between diet and regular sodas, examines the potential health effects of each, and provides guidance on how to identify diet soda and make informed choices.
Regular Soda vs. Diet Soda: What's the Difference?
Regular soda typically consists of carbonated water, sweeteners (such as high fructose corn syrup), "natural flavors," and caffeine. Diet sodas share a similar base, but the key difference lies in the sweetener. Instead of sugar or high fructose corn syrup, diet sodas use artificial sweeteners like aspartame, stevia, and sucralose.
Artificial Sweeteners: A Double-Edged Sword?
The debate over regular sugar versus sugar substitutes is complex, with pros and cons on both sides. While neither is considered truly healthy, the appeal of diet soda lies in its reduced calorie count. Many people believe that switching to diet soda will help them lose weight without sacrificing their favorite carbonated beverages. However, research suggests that artificial sweeteners may not be a perfect solution.
Some studies indicate that diet sodas may cause our brains to react to artificial sweeteners similarly to how they react to normal sodas. A discrepancy in calories may cause some to have a desire to ingest more calories in other areas. According to the Cleveland Clinic, some studies "found that people with overweight or obesity who switched to diet soda were likely to consume more calories in food than people with overweight or obesity who drank regular soda.” Furthermore, the people of this study showed a higher BMI than their counterparts who drank normal soda.
The Downside of Regular Soda
Regular soda is packed with sugar and empty calories. A single can can contain around 188 calories. These added sugars can lead to obesity and other health problems. Soda is not filling, making it easy to consume many calories throughout the day. The high sugar content in soda can also trigger the release of dopamine in the brain, stimulating pleasure centers and potentially leading to an addictive habit. As a whole, drinking regular soda can pose many problems to those who enjoy it on a regular basis.
Read also: The Truth About Diet Soda and Autism
Oral Health Concerns
Both diet and regular sodas can harm your oral health. The acidity of both can cause harm to your mouth by weakening and eroding enamel. These drinks also encourage bacteria to grow within one’s mouth. Bacteria and other germs can cause cavities, as well as other problems. In fact, one of the main leading causes of cavities is sugary drinks, such as Coke and Diet Coke. While Coca-Cola is one of the most popular soda brands by far, this is not the only place where it comes first: Coca-Cola, regular and diet, is also the most tooth-eroding soft drink you can drink, and this is proven by testing acidity rates.
Long-Term Health Risks
Both diet soda and regular soda have been linked to obesity, high cholesterol, and even heart disease. In recent years, soda consumption has decreased in the United States, with approximately 1 in 5 people drinking at least one soda daily.
Identifying Diet Soda: Taste, Labels, and Beyond
If you've ever taken a sip of a zero sugar soda and expected diet soda flavor, or vice versa, you already know: Not all sugar-free sodas taste the same.
Taste Differences
Diet Coke leans solely on aspartame, which gives it a sharper, more acidic flavor, while Coke Zero Sugar blends aspartame with acesulfame potassium (Ace-K) to create a rounder, sweeter sip that aims to mimic classic Coca-Cola. Pepsi follows a similar playbook - Diet Pepsi is aspartame-forward, while Pepsi Zero Sugar adds Ace-K to round out the sweetness. Dr Pepper takes another route: Diet Dr Pepper relies on aspartame, while Dr Pepper Zero Sugar uses aspartame plus Ace-K for more of that signature 23-flavor depth.
Zero sugar sodas have evolved since their launch, yet the purpose has stayed consistent: It's meant to taste like regular soda, just without the sugar. That's why many sodas use sweetener combos, which helps it land closer to the original's taste. For example, if you grew up on Diet Coke, Coke Zero might taste too sweet. If you're a Zero loyalist, Diet might hit too sharp or too metallic.
Read also: The Truth About Baking Soda and Coffee for Weight Loss
Decoding the Labels
Brands have moved away from the word "diet" in favor of "zero sugar," hoping to dodge outdated connotations of dieting. But for loyalists, the difference is clear. The most significant differences between Coke Zero and Diet Coke are in the taste and ingredients. They both contain aspartame, but Coke Zero also uses the sweetener acesulfame potassium and has less caffeine. Comparatively, Diet Coke more closely resembles the original Coca-Cola formula.
The "Sugar Bomb" Scenario
You ordered Diet Coke but is that what arrived? It tastes … funny. But you're not sure. Do your lips feel sticky? Or is that your imagination? Sugar-free or sugar-bomb? Living with diabetes, the difference between the Diet Coke we ordered and the regular Coke we're served isn't just a few extra calories.
Scott Johnson, the Patient Success Manager, US for mySugr and has lived well with diabetes for over 40 years, shared his experience about being a victim of the Diet Coke order gone wrong, a.k.a "The Sugar Bomb," is a hard lesson to swallow. So he's built safety checks into his drink orders, and sometimes they help. Whenever possible he tries to watch the server or attendant fill my drink cup, to make sure it's positioned under the proper fountain nozzle. He annunciates like crazy. And there's nothing like being at a place where he can fill his own drink. Plus, unlimited refills? There are times, though, when it's not possible to avoid a conversation with the server or employee. So he politely asks them to double-check and make sure it's diet. Sometimes the new drink tastes completely different, and it's clear the first one wasn't diet, and sometimes it tastes exactly the same.
The drink machines we see are only the front side of a complicated system with lots of tubes and hoses. Here's one behind the scenes example. Each flavor choice up front leads to a box of concentrated flavor syrup in the back. They are connected with a hose that delivers the flavored syrup to the nozzle, picking up chilled carbonated water on the way. We are counting on them to put the correct box there and connect the right hose.
There are three ways Scott Johnson can think of to be sure you don't get accidentally sugar-bombed by a Diet Coke order gone wrong.
Read also: Is Diet Mountain Dew Healthy?
Blood Glucose Testing
"What? Most of the time you can actually do a BG check with the drink to be sure. Note: This will affect your meter averages and reporting (because you're testing soda, not your blood…). Where possible, I'll include instructions for marking the test as a "control" reading which will be ignored in your meter statistics, but not all meters allow it.
- Control: Insert a test strip, but before applying anything to the strip press ↑ so that 'CtL' appears in the upper right corner of the display.
- Control: Insert a test strip, but before applying anything to the strip use ↑ to select "Control Solution" in the display.
- Control: Control solution is automatically detected and a Control Solution icon is displayed.
That's what happened when Scott tried testing both regular Coke and Diet Coke with the meters he had here. You should give it a try with your meter if you can spare a test strip or two. This box, for example, which can be used to measure both ketones and glucose, is listed at Amazon for about $25. For a few dollars cheaper, you can get the strips that just measure glucose, which is all you'd need to check your drinks.
Soda Guns and Freestyle Machines
If someone orders a regular Fanta Orange right before I order my Diet Coke, isn't there residual Fanta Orange in the tube before my Diet Coke comes out? I mean, I can taste the Fanta Orange, yo! Scott bet good bartenders flush the line a little before serving the next drink. And what about those super fancy Coca-Cola Freestyle machines? Scott really enjoy using them, but I don't know how they work. I hear they use flavor cartridges, almost like an inkjet printer. But it's all coming out of the same nozzle, man! Same problem as the nasty bartender drink-dongle!
Artificial Sweeteners Under Scrutiny
Alarmist headlines have dominated the media landscape since the World Health Organization (WHO) released its updated guidelines in May 2023 recommending against the use of NNS (non-nutritive sweeteners) to control body weight or reduce the risk of noncommunicable diseases. Aspartame is a NNS containing about 200 times the sweetness compared to table sugar and is one of the most commonly used NNS in diet soda. While the IARC’s classification may sound scary, it is important to keep things in perspective. For starters, the IARC is not a food safety agency. Instead, it is an intergovernmental branch of the WHO.
A recent study conducted in 2023 reported finding DNA damage occurring from the use of sucralose, a NNS with 600 times the sweetness compared to table sugar and sold under brand name Splenda. However, what the headlines often leave out is that the study didn’t reveal DNA damage from actual sucralose. Instead, researchers concluded damage to DNA resulted from the use of sucralose-6-acetate, a compound formed in trace amounts after sucralose is consumed and metabolized. Additionally, the study was conducted in vitro (outside the body) as opposed to in vivo (in the body), which would give us a better understanding of how sucralose or any metabolites affect our health.
Regulatory Guidelines
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. But 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.
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.
In a review of 29 studies, researchers linked aspartame with neurotoxic effects, such as behavioral concerns, mood disorders, and memory and learning impairments. (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.) Older research also associated aspartame with behavioral and cognitive problems - such as headaches, irritable mood, depression, and insomnia.
The Rise of Zero-Sugar Sodas
If you’re a regular in the soda aisle at the grocery store, you may have noticed an uptick in zero-sugar sodas in recent years. From Coca-Cola to Pepsi, Dr. Pepper, and Mountain Dew, most of the classic soda brands have branched out to provide this seemingly healthier option. Traditional diet versions, like Diet Coke, are still kicking around. But other soft drinks-like Diet Canada Dry, Diet Crush, and Diet A&W Cream Soda-have all been phased out and replaced in recent years by zero-sugar alternatives, which are reportedly not quite the same.
Even though it's been around since 2005, its manufacturer called Coke Zero “a bet for the future” due to its incredible growth in sales-5 percent in 2023, more than twice the growth of the brand’s portfolio in the same year. Other zero-sugar alternatives are becoming popular, too.
The Origins of Diet and Zero-Sugar Sodas
The first diet soda hit markets in 1952, and the industry has taken wild turns since. No-Cal, invented by Hyman Kirsch (a noted pioneer in the world of sugar-free soft drinks), replaced sugar with cyclamate, an artificial sweetener. The soda was initially intended for consumers with diabetes and cardiovascular issues. However, once No-Cal was on the shelves, it became clear that dieters were its primary demographic.
Diet-Rite Cola, which was released by the Royal Cola Company in 1958, was created to help people with diabetes and others who needed to limit their sugar intake. Instead of sugar, this soda was made with cyclamate and saccharin for added sweetness. By 1960, it was the fourth most popular soft drink, behind Coca-Cola, Pepsi, and 7-Up.
This led to the creation of drinks like TaB by the Coca-Cola Company, which was the top diet soda in the 1960s and 1970s. In 1963, Pepsi released Patio (renamed Diet Pepsi a year later) to immediate popularity and celebrity endorsements (fans of Mad Men might even remember it). However, Diet Coke wasn’t released until 1982, largely due to concerns about associating the word diet with the iconic Coke trademark. (The drink became a smashing success.)
Zero-sugar sodas really only began making waves in the 2000s. Compared to diet sodas, these soft drinks were heavily marketed to Millennials (and later, Gen Z) but weren’t advertised in quite the same way as sugar-free sodas were to Boomers or Gen X in previous decades. These drinks were positioned as ideal for consumers invested in their health who were seeking low-calorie, no-sugar alternatives to their favorite soft drinks. For consumers, the most obvious difference for Coke Zero might be right on the label-an aversion to the word diet. Taste of Home reports Greg Lyons, chief marketing officer of PepsiCo North America, has said, “No Gen Z wants to be on a diet these days. Younger people just don’t like the word diet.”
Healthier Alternatives to Soda
In order to continue decreasing soda consumption, it is important we implement ways to stop desiring regular soda and diet soda. Healthier alternatives can be used in place of soda as people begin to stop drinking it. Some people drink soda because it provides caffeine. Some replacements that provide the same effect could be green tea or coffee. Other people drink soda because they like the fizzing sensation it provides. Differing alternatives that are still carbonated are seltzers or sparkling water. The best replacement for regular and diet soda is water. Water can be enhanced by adding flavoring drops if necessary.