Does Diet Soda Raise Blood Sugar | Health Risks and Diabetes

Does diet soda have sugar? 

The American Heart Association (AHA) recommends limiting added sugars to (1):

• Six teaspoons (24 grams, or 100 calories) per day for women 
• Nine teaspoons (37.5 grams, or 150 calories) per day for men
• Less than six teaspoons per day for children ages 2‒18
• Zero for children under two years old 

Surprisingly, the average American consumes 22 teaspoons of sugar daily (2). That’s two to three times more than what is recommended.

Among sugar sources, sugary drinks are the real troublemakers, accounting for 33% of all the added sugar in the typical American diet (2). Notably, that seemingly harmless can of regular cola hides 48.9 grams of sugar inside (3).

To rock this sugar-savvy lifestyle, some may try diet sodas, which contain no sugar or calories but are still packed with a familiar taste punch (4). 

With these properties, no wonder diet sodas and other low-calorie sweetener drinks have become a hit. They make up almost one-third of the beverage choices in the US (1). 

Yet, are they guilt-free go-to for those craving a sweet fix?

How are diet sodas sweetened without sugar?

Adding artificial sweeteners to diet sodas could achieve the same sweet taste without a gram of sugar. These sweeteners are 200‒20,000 times sweeter than table sugar or sucrose (5). 

The US Food and Drug Administration (FDA) has approved six types of artificial sweeteners (5, 6): 

• Aspartame, as in Nutrasweet, Equal, and Sugar Twin
• Saccharin, including Sweet and Low, Sweet Twin, Sweet’N Low, and Necta Sweet
• Sucralose, as in Splenda
• Acesulfame potassium (or Ace-K), including Sunett and Sweet One
• Neotame
• Advantame

So, does Diet Dr. Pepper have sugar? It is a sugar-free version of Dr. Pepper that is sweetened with aspartame, Ace-K, or sucralose instead. 

Diet Coke in stores contains aspartame, sometimes mixed with sucralose. The food industry enhances Coke Zero Sugar with aspartame and Ace-K. Fountain Diet Coca-Cola combines aspartame and saccharin (7).

Among them, aspartame is one of the most commonly used artificial sweeteners. It may add up some calories but far less than sugar. Thus, it is considered a “nutritive sweetener” (8).

If you have a rare genetic disease called phenylketonuria (or PKU), be careful with aspartame, or it’s best to avoid it to prevent digestive and brain problems (5, 9).  

Other zero-calorie sweeteners are considered “non-nutritive sweeteners” (8).

How does diet soda affect blood sugar?

Artificial sweeteners in diet sodas do not directly affect blood sugar or insulin (the hormone responsible for lowering blood sugar levels). Acesulfame potassium, saccharin, and sucralose can traverse the body intact without undergoing metabolic breakdown (46, 47).

However, these sweeteners may complicate blood sugar management.

It’s commonly believed that keeping your body mass index (BMI) in check can help manage blood sugar. However, those who regularly consume diet sodas tend to have a higher BMI (11, 23, 48).

Artificial sweeteners can upset your gut microbiomes (those microbes in your gut), causing an imbalance known as dysbiosis. This disruption can then lead to gut inflammation and difficulties in processing sugar, driving glucose intolerance (49, 50, 51). 

In exchange, such sweeteners can raise the probability of obesity, insulin resistance (where your body becomes less responsive to insulin), and type 2 diabetes (36, 52). 

How does diet soda spike insulin?

Drinking diet soda alone does not directly raise your insulin resistance (53).

Conversely, even though artificial sweeteners in diet sodas are not digested in the gastrointestinal system, they can still send signals that affect insulin function with prolonged consumption (12, 36).

Beyond carbs in diet soda—What’s really at stake?

When artificial sweeteners interfere with the beneficial microbiome in your gut, it will trigger insulin resistance (36).

GLP-1 (a hormone that triggers insulin release) secretion could be another way to measure glucose control. Interestingly, when people drink diet soda, their bodies may secrete more GLP-1, thus producing more insulin (48, 54). 

One explanation for this is diet sodas may activate the sweet taste receptors on your tongue. In turn, they can increase GLP-1 levels (after a 75-g glucose load) by 34% in healthy people and 43% in type 1 diabetes, but not in type 2 diabetes (48, 55).

So even when your blood sugar is unaffected by artificial sweeteners, there still could be an uptick in insulin levels. 

Does Coke Zero raise blood sugar and insulin? The truth behind

Diet sodas like No-Cal, Tab, and Diet Coke for people with diabetes were first made in the 1950s and 1960s. This was a time when many people started caring about the calories they ate. Since then, diet sodas have become very popular, and Coke Zero made its way in 2005, offering the taste of a cola beverage (56). 

Coke Zero’s sweetness comes from a mix of aspartame and acesulfame potassium (Ace-K). While they don’t cause an immediate rise in blood sugar or insulin, they could affect insulin sensitivity over time (36).

Another problematic compound in Diet Coke is caffeine, with an amount of 46 mg for each can. Caffeine has been shown to raise blood sugar and insulin levels after eating sugar (57).

Acute caffeine intake may lower your insulin sensitivity. This means that in the short term, caffeine may cause high blood sugar (57, 58).

How do artificial sweeteners in diet soda affect your health?

Diet sodas are mostly water, with almost no calories and a little sodium per serving. They may also contain some additives, each with its function (4, 9, 10):

• Artificial flavors
• Artificial colors: caramel, carotenoids, or anthocyanins
• Acidic ingredients: phosphoric, citric, or malic acid
• Preservatives: sodium or potassium benzoate
• Caffeine

Some soda companies add vitamins and minerals to their diet sodas. It’s their way of making these products seem like the healthier choice (10).

However, the amount of beneficial nutrients in fortified diet sodas is minor. You can easily get them from vegetables and fruits (with much greater content). Therefore, diet sodas have no special benefits. 

Their main use is to help people cut down on calories, often seen as a way to lose weight and avoid chronic health issues. Yet, there’s no concrete proof to back up that assumption (11). 

On the other hand, these tempting beverages may come with a few health concerns. 

In a 2016 review, various studies found no connection between drinking soda and adverse health effects. However, all of them were funded by companies in the soda industry (12). 

When soda companies put their money where the research is, the results are more positive about soda’s health effects. It may make us question how reliable those findings are (13).

Many other large-scale, long-term studies have shown that drinking diet soda can set you up for many health risks, including brain and heart diseases. Some potential problems including (14, 15, 16, 17):

• 14% increase in high blood pressure
• 59% increase in larger waist size
• 23‒53% increase in metabolic syndrome
• 38‒68% increase in diabetes
• 31% higher risk of depression
• 27% higher risk of stroke caused by bleeding
• 30‒43% higher risk of heart attack and stroke
• 50% higher risk of dying from heart problems
• 30% higher risk of dying from any cause
• Triple stroke and Alzheimer’s disease risk (People aged >45)
• Double the risk of kidney function decline

These studies considered multiple factors affecting the results—age, lifestyle, and family history. Interestingly, they still found solid evidence pointing to an increased risk  in (14):

Increased appetite

According to a study, sucralose could make women and people with obesity crave and eat more food. They had more robust brain responses to artificial sweeteners than regular sugar-sweetened drinks (18).

Other studies suggest that diet soda drinkers showed more activity in parts of the brain associated with reward (the midbrain and amygdala). Thus, it might trigger sweet cravings and even create sugar addiction (19, 20, 21).

Moreover, the carbon dioxide in sodas may drive your stomach cells to produce more ghrelin, which is the hormone that makes you feel hungry (22).

Overweight and obesity

The zero-calorie diet sodas can easily make you believe you’re being healthy. Yet it could also lead you to eat more unhealthy food as a ‘reward.’

Over time, people who drink diet sodas daily may be more susceptible to weight gain, stubborn belly fat, and an elevated BMI.

Consequently, they may become overweight or obese (11, 14, 23).

The more diet soda people drink, the bigger the increase in waist size, which may entail various metabolic issues (24).

Diabetes

Can diet soda cause diabetes? Unfortunately, consuming diet soda is associated with elevated A1c levels, meaning your body has difficulty keeping your blood sugar at bay (25).

Studies found that daily diet soda intake was associated with a 67% higher risk of landing in the type 2 diabetes zone (26).

High blood pressure (hypertension)

In a large study, people who drank one or more artificially sweetened drinks daily had a 14% likelihood of high blood pressure. Those carbonated, cola-infused sodas packed an even higher risk (2, 28).

Dental decay

Despite being sugar-free, diet soda can still wreak havoc on your smile. Its acidic nature can gradually erode your enamel, making your teeth more sensitive and leaving them susceptible to cavities (29, 30). 

Carbon dioxide inside fizzy soda is the troublemaker contributing to its acidic environment. The acidity may also come from citric, malic, and phosphoric acids, which are used to make soda drinks taste tart (31, 32, 33).

Dentists often recommend that cutting down on soda is a crucial part of your healthy diet (29).

Depression

In older people, going overboard with more than four cans of diet soft drinks daily was associated with a 31% increased risk of depression. In contrast, regular soft drink sippers are associated with a 22% risk increase of depression (16). 

Even less than a can of regular soft drinks (containing table sugar) a day may have its share of depression risks. However, they’re lower than their diet counterparts (16).

Cancer

Only a few studies have examined the link between artificial sweetener intake from all dietary sources and cancer. One study in 2022 reported cancer incidence in more than 102,000 French adults and the association with artificial sweeteners (34). The 2022 study found that people who consumed larger quantities of sweeteners (above 17‒19 mg/day and followed them for almost eight years) had a 13% increased risk of developing cancer ) compared to non-consumers (34, 35).

Furthermore, the study pinpointed aspartame as a factor contributing to a 22% higher risk of breast cancer and a 15% higher risk of cancers by 15% related to obesity.

Acesulfame-K can also upsurge the risk by 13%. 

No link was found between sucralose and cancer risk (34). 

Gut health

The sweeteners in diet soda may harm the beneficial bacteria in your gut, which are essential for digestion and your immune system. Sucralose, aspartame, ace-k, and saccharin can all upset the balance and diversity of your gut microbiomes (36, 37).

Kidney (renal) health

A study spanning 25 years found that people who drank more than seven glasses of diet soda per week had an 83% higher chance of developing kidney disease (38) caused by the phosphorus content in sodas, which could put too much acid in the kidneys (4, 39).

Bone health

Studies found that people who drank soft drinks (but not diet soda) every day were 4.69 times more likely to get a fracture compared to non-drinkers over five years (40) due to their caffeine and phosphorus content (41, 42, 43). 

Another significant research on women after menopause found that having one diet soda daily increased the risk of hip fracture by 12% (17). Drinking carbonated beverages is also linked to a higher risk of bone fractures in teenage girls who are physically active (41).

Pregnancy

In a study of more than 60,000 pregnant women, those who drank more artificially sweetened carbonated drinks, including diet sodas, increased their likelihood of having a child with asthma by 30% as compared to non-consumers (44).

These women were also 31% more likely to report their child experiencing allergic rhinitis during the next seven years than non-consumers, though it was not statistically significant.

In another study, infants whose mothers drank artificial sweeteners every day had double the risk of obesity by age one compared to those whose mothers didn’t drink. In this case, choosing sugary beverages was a better option (45).

Is it safe for people with diabetes to drink diet soda?

Unfortunately, most artificial sweeteners in diet sodas don’t have any positive effects on managing diabetes. They may even increase the risk of developing pre-diabetes and diabetes by targeting hormones (50, 59, 60). 

One study of 200 diabetic patients found a correlation between diet soda and artificial sweetener intake and diabetic retinopathy (25).

In turn, the American Diabetic Association recommends diet soda should be avoided in the setting of diabetes (61).

The existing research quality has been limited (most deal with healthy individuals), making it difficult to draw definitive conclusions about whether people with diabetes can drink diet soda safely (48, 25).

The key is to exercise restraint. You can opt for diet sodas occasionally when you have a strong sweet tooth. Still, try to stay moderate (1).

Alternative healthy drinks for people with diabetes

For optimal hydration, nothing beats water (1, 62). While some may find plain water dull, there are various exciting options beyond diet sodas.

Let’s add a burst of flavor to your water to add enjoyment (22, 63):

• Some fruit slices, such as cucumber or berries, for a detoxifying fragrance
• Puréed fruit, like passion fruit or mango, for a guilt-free sweet kick
• a splash of fruit juice like lime or lemon, but not from concentrated juice sold at the supermarket
• Herbs like basil, cinnamon, ginger, or mint for a refreshing taste
• Herbal infusions, including citrus, lavender, chamomile, peppermint, and hibiscus tea

If you like sodas because of their fizzy feeling, opt for (62, 64): 

• Seltzer water or sparkling water 
• Kombucha is a refreshing fermented tea with probiotics that help with fermentation, where the sugar is converted into healthy organic acids

Don’t suddenly stop drinking diet sodas containing caffeine to avoid caffeine withdrawal headaches, especially if you drink them daily (65).

Instead, gradually remove them from your diet or consider unsweetened tea or black coffee for a quick caffeine boost. They may also be packed with antioxidants and beneficial nutrients (66).

When your sweet tooth strikes, there are numerous healthier options available to fulfill your desire: 

• Stevia, a natural sweetener that is 450 times sweeter than sucrose. Stevia leaves also contain antioxidants that help prevent heart disease, atherosclerosis, and cancer (5, 67). 

Erythritol, a sugar alcohol from corn, is 60‒80% as sweet as sugar. This sweetener doesn’t usually cause digestive problems or make your blood sugar or insulin levels go up. It can even help protect your cells from damage when you eat other sugary foods (68).