Is Coke Zero (Coca-Cola Without Sugar) Healthy?

Coke Zero, which has recently been rebranded as Coca-Cola Zero Sugar, is marketed as a healthier version of the original sugar-sweetened beverage, Coca-Cola Classic.

It contains zero calories and sugar while providing the signature Coca-Cola flavor, making it an appealing drink among those trying to reduce their sugar intake or control their weight.

This article takes a detailed look at Coke Zero and explains whether it’s a healthy choice.

Zero nutritional value

Coke Zero does not provide any calories and is not a significant source of nutrition.

One 12-ounce (354-ml) can of Coca-Cola Zero Sugar (Coke Zero) offers (1):

  • Calories: 0
  • Fat: 0 grams
  • Protein: 0 grams
  • Sugar: 0 grams
  • Sodium: 2% of the Daily Value (DV)
  • Potassium: 2% of the DV

To sweeten this beverage without adding calories, artificial sweeteners are used.

The health effects of artificial sweeteners are controversial, and concern regarding their safety is growing (2Trusted Source).

Though the research is inconsistent, some studies find that the use of artificial sweeteners may contribute to the development of obesity and metabolic syndrome, a cluster of conditions that increase disease risk (3Trusted Source, 4Trusted Source, 5Trusted Source).

Coca-Cola Zero Sugar (Coke Zero) uses several common artificial sweeteners, including aspartame and acesulfame potassium (Ace-K). The remaining ingredients are carbonated water, caramel color, food additives, and natural flavors (1).

The only differences between Coke Zero and the new rebrand — Coca-Cola Zero Sugar — are minor changes to the natural flavor composition (6).


Coke Zero does not contain any calories or sugar and is not a significant source of nutrients. It’s sweetened with artificial sweeteners, which have controversial health effects.

Artificial sweeteners and weight loss

Research results on the effects of Coke Zero and other artificially sweetened beverages on weight loss are mixed.

One 8-year observational study found that people who drank more than 21 artificially sweetened beverages per week almost doubled their risk of overweight and obesity, compared with people who didn’t consume these kinds of drinks (7Trusted Source).

The same study noted that total daily calorie intake was lower in individuals who drank diet beverages despite their increase in weight. This suggests that artificial sweeteners may influence body weight in other ways than calorie intake (7Trusted Source, 8Trusted Source, 9Trusted Source).

Another study observed that drinking diet soda was associated with greater waist circumference over 9–10 years (10Trusted Source).

On the other hand, many human intervention studies indicate that the use of artificial sweeteners is either neutral or beneficial for weight management.

In one 6-month, randomized, controlled study, people with overweight or obesity experienced moderate weight loss of 2–2.5% of their body weight when replacing caloric beverages with diet beverages or water (11Trusted Source).

In another study, people in a 12-week weight loss program who drank artificially sweetened beverages lost 13 pounds (6 kg), while those drinking water lost 9 pounds (4 kg) (12Trusted Source).

Thus, the evidence on the effects of artificially sweetened beverages on weight management are conflicting, and more research is needed.


The evidence on the use of Coke Zero and other artificially sweetened drinks for weight management is conflicting. More research is needed to understand the benefits and risks of diet beverages.

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Diet sodas and tooth erosion

Similarly to regular soda, drinking diet sodas like Coke Zero is associated with an increased risk of tooth erosion.

One of the main ingredients in Coke Zero is phosphoric acid.

One study on human teeth noted that phosphoric acid causes mild enamel and tooth erosion (13Trusted Source).

Another study observed that Coca-Cola Light (Diet Coke), which differs from Coke Zero only in that it contains both phosphoric and citric acid, caused enamel and tooth erosion in freshly extracted cow’s teeth in just 3 minutes (14Trusted Source, 15).

Still, keep in mind that citric acid has been found to erode teeth more than phosphoric acid, which suggests that Coke Zero may affect tooth enamel slightly less than Diet Coke (13Trusted Source).

Additionally, Diet Coke had less erosive effects than other beverages, such as Sprite, Mountain Dew, and apple juice (14Trusted Source).


The acidic pH level of Coke Zero is associated with an increased risk of enamel and tooth erosion, though it may affect your teeth less than other acidic beverages.

Coke Zero and diabetes risk 

Coke Zero is sugar-free. However, the sugar substitutes it contains may not necessarily be a healthier option for people looking to reduce their risk of diabetes.

A 14-year study in 66,118 women observed an association between drinking artificially sweetened beverages and an increased risk of type 2 diabetes (16Trusted Source).

Another study in 2,019 people showed a link between both sugar-sweetened drinks and artificially sweetened diet beverages and type 2 diabetes, suggesting that switching to diet soda may not lower your diabetes risk (17Trusted Source).

What’s more, in an 8-year study in 64,850 women, consuming artificially sweetened beverages increased the risk of diabetes by 21%, though the risk for those drinking sugar-sweetened beverages was even higher at 43% (18Trusted Source).

Interestingly, other studies have found opposing results.

A 14-year study in 1,685 middle-aged adults did not find any association between diet soda intake and an increased risk of prediabetes (19Trusted Source).

The results from these studies are conflicting and don’t provide an exact explanation of how artificially sweetened beverages increase your risk of diabetes. Therefore, more research is needed.


Though Coke Zero is sugar-free, its artificial sweeteners are controversial. Still, research on the effects of artificial sweeteners on diabetes risk is mixed, and more studies are needed to fully understand a possible connection.

Other potential downsides

Artificially sweetened beverages like Coke Zero have been linked to other health issues, including:

  • Increased risk of heart disease. An observational study found a link between artificially sweetened beverages and an increased risk of heart disease among women with no prior history of heart disease (20Trusted Source).
  • Increased risk of kidney disease. The high phosphorus content in sodas may cause kidney damage. A study noted that those who drink more than 7 glasses of diet soda per week doubled their risk of kidney disease (21Trusted Source).
  • Could alter your gut microbiome. Several studies indicate that artificially sweetened beverages can alter your gut microbiome, causing poor blood sugar control (22Trusted Source, 23Trusted Source).
  • May increase osteoporosis risk. One study observed that daily cola intake was associated with a lower bone mineral density of 3.7–5.4%. Similar results were found for those who drank diet cola beverages (24Trusted Source).

Further research is needed to determine the exact effects of Coke Zero and other diet beverages on your health.


Coke Zero and other diet sodas are linked to alterations in the gut microbiome and an increased risk of osteoporosis and heart and kidney disease. However, more research is needed.

The bottom line

Coke Zero does not add nutritional value to your diet, and the long-term effects of drinking diet sodas are still unclear.

If you want to reduce your sugar or regular soda intake, opt for healthier, low-sugar drinks like herbal tea, fruit-infused water, and black coffee — and leave Coke Zero on the shelf.ADVERTISEMENTHealthy eating shouldn’t be a hassle

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How Much Caffeine Do Coke and Diet Coke Contain?

Coca-Cola Classic — commonly simply referred to as Coke — and Diet Coke are popular beverages around the world.

However, soft drink consumption has been associated with many health concerns, ranging from weight gain to high blood sugar (1Trusted Source, 2Trusted Source).

Not only that, but Coke and Diet Coke also contain a hearty dose of caffeine, which can be problematic for those looking to cut down their caffeine consumption.

This article compares the caffeine contents of Coke, Diet Coke and other beverages and tells you how it could affect your health.

What Is Caffeine?

Caffeine is a naturally-occurring chemical that acts as a central nervous system stimulant, enhancing alertness and fighting off fatigue.

It can be found in the leaves, seeds and fruits of many plants and is especially prevalent in cocoa beans, tea leaves and coffee beans (3).

It’s also commonly added to many products, including soft drinks, energy drinks and certain over-the-counter medications.

Nowadays, caffeine tops the charts as one of the most commonly consumed ingredients around the world (4Trusted Source).

In fact, it’s estimated that 85% of the US population consumes at least one caffeinated beverage per day, with an average daily intake of 165 mg of caffeine.

While coffee accounts for the majority of caffeine intake across the board, carbonated soft drinks like Coke make up a high proportion of the intake in those younger than 18 (5Trusted Source).


Caffeine is a natural stimulant found in many products including coffee, soft drinks, energy drinks and over-the-counter medications. Soft drinks account for a higher proportion of the intake in people younger than 18.

How Much Caffeine Is in Coke and Diet Coke?

The caffeine content of Coke products depends on several factors, including the serving size and type of drink (6):

7.5-ounce (222-ml) can12-ounce (355-ml) can20-ounce (591-ml) bottle
Coke21 mg caffeine32 mg caffeine53 mg caffeine
Diet Coke28 mg caffeine42 mg caffeine70 mg caffeine

Decaffeinated varieties, such as caffeine-free Coca-Cola, are also available for those looking to cut their caffeine intake.


Coke contains 32 mg of caffeine per 12-ounce (335-ml) serving. Diet Coke is higher in caffeine, with about 42 mg per 12 ounces (335 ml).

How the Caffeine in Coke Compares

Ounce for ounce, the amounts of caffeine in Coke and Diet Coke are significantly lower than most other caffeinated beverages including energy drinks, coffee and green tea (4Trusted Source, 7, 8):

Serving sizeCaffeine content
Coke7.5 ounces (222 ml)21 mg
Diet Coke7.5 ounces (222 ml)28 mg
Green tea8 ounces (237 ml)35 mg
Energy drinks8.3 ounces (245 ml)77 mg
Coffee8 ounces (237 ml)95 mg

Keep in mind, however, that the caffeine content varies for these drinks based on different factors, including brand, ingredients and specific type of beverage.


Coke and Diet Coke are generally lower in caffeine than other caffeinated beverages, including energy drinks, coffee and tea.

Why Caffeine Intake Matters for Some

Caffeine consumption can have several benefits for your health.

In particular, research shows that it may increase metabolism, improve exercise performance and boost alertness (9Trusted Source, 10Trusted Source, 11Trusted Source).

However, it can also come with negative side effects, especially for people who are sensitive to its effects.

Caffeine can be addictive, and some research indicates that genetic variations could cause people to respond differently to it (12Trusted Source, 13Trusted Source).

Caffeine intake has also been shown to affect mental health, with one study in 2,307 children associating increased caffeine consumption with higher levels of perceived anxiety and depression (14Trusted Source).

Excess intake can also cause other side effects, including headaches, high blood pressure and sleep disturbances (15Trusted Source, 16Trusted Source, 17Trusted Source).

Additionally, it’s recommended that women who are pregnant or breastfeeding limit their caffeine intake, as it may be linked to a higher risk of miscarriage and low birth weight (18Trusted Source, 19Trusted Source).


Caffeine consumption has been linked to improvements in metabolism, exercise performance and alertness. However, it can also be addictive and may cause a wide range of side effects in some people.

How Much Caffeine Is Too Much?

When consumed in moderation, caffeine can be used safely with minimal risk of side effects.

In fact, doses up to 400 mg daily are considered safe for most adults (20Trusted Source).

Ideally, though, it’s best to limit your intake to around 200 mg daily to reduce your risk of side effects.

For reference, this equals just two 8-ounce (237-ml) cups of coffee or around five 8-ounce (237-ml) cups of green tea.

However, you would need to drink more than six 12-ounce (355-ml) cans of Coke or four 12-ounce (355-ml) cans of Diet Coke per day to reach this amount.


400 mg of caffeine daily is considered safe for most adults, but cutting your intake to 200 mg daily can help reduce your risk of adverse side effects.

The Bottom Line

Coke and Diet Coke contain 32 and 42 mg of caffeine per 12 ounces (335 ml) respectively, which is lower than other caffeinated beverages like coffee, tea and energy drinks.

However, they’re often high in sugar and other unhealthy ingredients, so keep your intake to a minimum to promote better health. Instead, opt for other natural sources of caffeine in moderation, such as coffee or tea, to maximize the potential health benefits.ADVERTISEMENTStart a custom weight loss program

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Diet Soda: Good or Bad?

Diet sodas are popular beverages all over the world, especially among people who want to reduce their sugar or calorie intake.

Instead of sugar, artificial sweeteners, such as aspartame, cyclamates, saccharin, acesulfame-k, or sucralose, are used to sweeten them.

Almost every popular sugar-sweetened beverage on the market has a “light” or a “diet” version — Diet Coke, Coke Zero, Pepsi Max, Sprite Zero, etc.

Diet sodas were first introduced in the 1950s for people with diabetes, though they were later marketed to people trying to control their weight or reduce their sugar intake.

Despite being free of sugar and calories, the health effects of diet drinks and artificial sweeteners are controversial.

Diet soda isn’t nutritious

Diet soda is essentially a mixture of carbonated water, artificial or natural sweetener, colors, flavors, and other food additives.

It usually has very few to no calories and no significant nutrition. For example, one 12-ounce (354-mL) can of Diet Coke contains no calories, sugar, fat, or protein and 40 mg of sodium (1).

However, not all sodas that use artificial sweeteners are low in calories or sugar-free. Some use sugar and sweetener together. For example, one can of Coca-Cola Life, which contains the natural sweetener stevia, contains 90 calories and 24 grams of sugar (2).

While recipes differ from brand to brand, some common ingredients in diet soda include:

  • Carbonated water. While sparkling water can occur in nature, most sodas are made by dissolving carbon dioxide into water under pressure (4).
  • Sweeteners. These include common artificial sweeteners, such as aspartame, saccharin, sucralose, or an herbal sweetener like stevia, which are 200–13,000 times sweeter than regular sugar (4, 5Trusted Source).
  • Acids. Certain acids, such as citric, malic, and phosphoric acid, are used to add tartness to soda drinks. They’re also linked to tooth enamel erosion (4).
  • Colors. The most commonly used colors are carotenoids, anthocyanins, and caramels (4).
  • Flavors. Many different kinds of natural juices or artificial flavors are used in diet soda, including fruits, berries, herbs, and cola (4).
  • Preservatives. These help diet sodas last longer on the supermarket shelf. A commonly used preservative is potassium benzoate (4).
  • Vitamins and minerals. Some diet soft drink manufacturers add vitamins and minerals to market their products as healthier no-calorie alternatives (4).
  • Caffeine. Just like regular soda, many diet sodas contain caffeine. A can of Diet Coke contains 46 mg of caffeine, while Diet Pepsi contains 35 mg (1, 6).


Diet soda is a mixture of carbonated water, artificial or natural sweeteners, colors, flavors, and extra components like vitamins or caffeine. Most varieties contain zero or very few calories and no significant nutrition.

Effects on weight loss are conflicting

Because diet soda is usually calorie-free, it would be natural to assume it could aid weight loss. However, research suggests the association may not be so straightforward.

Several observational studies have found that using artificial sweeteners and drinking high amounts of diet soda is associated with an increased risk of obesity and metabolic syndrome (7Trusted Source, 8Trusted Source, 9Trusted Source, 10Trusted Source).

Scientists have suggested that diet soda may increase appetite by stimulating hunger hormones, altering sweet taste receptors, and triggering dopamine responses in the brain (11Trusted Source, 12, 13Trusted Source, 14).

Given that diet soft drinks have no calories, these responses may cause a higher intake of sweet or calorie-dense foods, resulting in weight gain. However, evidence of this is not consistent in human studies (5Trusted Source, 11Trusted Source, 15Trusted Source).

Another theory suggests that diet soda’s correlation to weight gain may be explained by people with bad dietary habits drinking more of it. The weight gain they experience may be caused by their existing dietary habits — not diet soda (16Trusted Source, 17Trusted Source).

Experimental studies do not support the claim that diet soda causes weight gain. In fact, these studies have found that replacing sugar-sweetened drinks with diet soda can result in weight loss (18Trusted Source, 19Trusted Source).

One study had overweight participants drink 24 ounces (710 mL) of diet soda or water per day for 1 year. At the end of the study, the diet soda group had experienced an average weight loss of 13.7 pounds (6.21 kg), compared with 5.5 pounds (2.5 kg) in the water group (20Trusted Source).

However, to add to the confusion, there’s evidence of bias in the scientific literature. Studies funded by the artificial sweetener industry have been found to have more favorable outcomes than non-industry studies, which may undermine the validity of their results (21Trusted Source).

Overall, more high quality research is needed to determine the true effects of diet soda on weight loss.


Observational studies link diet soda with obesity. However, it’s not clear whether diet soda is a cause of this. Experimental studies show positive effects on weight loss, but these might be influenced by industry funding.

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Some studies link diet soda to diabetes and heart disease

Although diet soda has no calories, sugar, or fat, it has been linked to the development of type 2 diabetes and heart disease in several studies.

Research has found that just one serving of an artificially sweetened drink per day is associated with an 8–13% higher risk of type 2 diabetes (22Trusted Source, 23Trusted Source).

A study in 64,850 women noted artificially sweetened drinks were associated with a 21% higher risk of developing type 2 diabetes. However, this was still half the risk associated with regular sugary drinks. Other studies have observed similar results (24Trusted Source, 25Trusted Source, 26Trusted Source, 27Trusted Source).

Conversely, a recent review found that diet soda is not associated with an increased risk of diabetes. Also, another study concluded that any association could be explained by the existing health status, weight changes, and body mass index of participants (28Trusted Source, 29Trusted Source).

Diet soda has also been linked to increased risks of high blood pressure and heart disease.

A review of four studies including 227,254 people observed that for each serving of artificially sweetened beverage per day, there is a 9% increased risk of high blood pressure. Other studies have found similar results (30Trusted Source, 31Trusted Source, 32Trusted Source).

Additionally, one study has linked diet soda to a small increase in the risk of stroke, but this was only based on observational data (33Trusted Source).

Because most of the studies were observational, it may be that the association could be explained another way. It’s possible that people who were already at risk of diabetes and high blood pressure chose to drink more diet soda (24Trusted Source, 34Trusted Source, 35Trusted Source).

More direct experimental research is needed to determine whether there’s any true causal relationship between diet soda and increased blood sugar or blood pressure.


Observational studies have linked diet soda to type 2 diabetes, high blood pressure, and an increased risk of stroke. However, there’s a lack of research on the possible causes of these results. They may be due to preexisting risk factors like obesity.

Diet soda and kidney health

Drinking diet soda has been linked to an increased risk of chronic kidney disease.

A recent study analyzed the diets of 15,368 people and found that the risk of developing end-stage kidney disease increased with the number of glasses of diet soda consumed per week.

Compared with those who consumed less than one glass per week, people who drank more than seven glasses of diet soda per week had nearly double the risk of developing kidney disease (36Trusted Source).

A suggested cause for the kidney damage is the high phosphorus content of soda, which may increase the acid load on the kidneys (36Trusted Source, 37Trusted Source).

However, it has also been suggested that people consuming high amounts of diet soda may do so to compensate for other poor dietary and lifestyle factors that may independently contribute to the development of kidney disease (36Trusted Source, 38Trusted Source).

Interestingly, studies investigating the effects of diet soda on the development of kidney stones have found mixed results.

One observational study noted that diet soda drinkers have a slightly increased risk of kidney stone development, but the risk was much smaller than the risk associated with drinking regular soda. In addition, this study has not been supported by other research (39Trusted Source).

Another study reported that the high citrate and malate content of some diet sodas may help treat kidney stones, particularly in people with low urine pH and uric acid stones. However, more research and human studies are needed (40Trusted Source).


Observational studies have found an association between drinking a lot of diet soda and the development of kidney disease. If diet soda does cause this, a potential reason could be increased acid load on the kidneys due to its high phosphorus content.

It’s linked to preterm delivery and childhood obesity

Drinking diet soda while pregnant has been linked to some negative outcomes, including preterm delivery and childhood obesity.

A Norwegian study in 60,761 pregnant women found that intake of artificially sweetened and sugar-containing drinks was associated with an 11% higher risk of preterm delivery (41Trusted Source).

Earlier Danish research supports these findings. A study in almost 60,000 women found that women who consumed one serving of diet soda per day were 1.4 times more likely to deliver preterm than those who did not (42Trusted Source).

However, recent research in 8,914 women in England did not find any association between diet cola and preterm delivery. However, the authors admitted that the study may not have been big enough and had been limited to diet cola (43Trusted Source).

It’s important to note that these studies were only observational and offer no explanation of exactly how diet soda may contribute to preterm birth.

Furthermore, consuming artificially sweetened drinks while pregnant is significantly associated with an increased risk of childhood obesity (44Trusted Source).

One study found that the daily consumption of diet drinks during pregnancy doubled the risk of a baby being overweight at 1 year of age (45Trusted Source).

Further research is needed to analyze the potential biological causes and long-term health risks for children exposed to artificially sweetened sodas in the womb.


Large studies have linked diet soda to preterm delivery. However, a causal link has not been found. Additionally, infants of mothers who drank diet soda while pregnant are at an increased risk of being overweight.

Other effects

There are several other documented health effects of diet sodas, including:

  • May reduce fatty liver. Some studies have shown that replacing regular soda with diet soda can reduce fat around the liver. Other studies have found no effect (46Trusted Source, 47).
  • No increase in reflux. Despite anecdotal reports, carbonated drinks have not been found to make reflux or heartburn worse. However, the research is mixed, and more experimental studies are needed (3Trusted Source, 48Trusted Source).
  • No strong links to cancer. Most of the research on artificial sweeteners and diet soda has found no evidence it causes cancer. A slight increase in lymphoma and multiple myeloma in men was reported, but the results were weak (49Trusted Source, 50Trusted Source).
  • Changes to the gut microbiome. Artificial sweeteners may alter the gut flora, leading to reduced blood sugar control and potentially increasing the risk of type 2 diabetes. One study found all of the six tested artificial sweeteners damaged the gut microbiome in various ways. Another found the way people’s gut flora reacted to artificial sweeteners was highly individualized (51Trusted Source, 52Trusted Source, 53, 54Trusted Source).
  • Increased risk of osteoporosis. Diet and regular cola is associated with bone mineral density loss in women, but not in men. The caffeine and phosphorus in cola might interfere with normal calcium absorption (5Trusted Source).
  • Tooth decay. Like regular soda, diet soda is associated with dental erosion due to its acidic pH level. This comes from the addition of acids, such as malic, citric, or phosphoric acid, for flavor (5Trusted Source, 55Trusted Source).
  • Linked to depression. Observational studies have found higher rates of depression among those who drank four or more diet or regular sodas per day. However, experiments are needed to determine whether diet soda is a cause (56Trusted Source).

While some of these results are interesting, more experimental research is needed to determine whether diet soda causes these issues, or if the findings are due to chance or other factors.


Diet soda may improve fatty liver and does not appear to increase heartburn or the risk of cancer. However, it may reduce blood sugar control and increase the risks of depression, osteoporosis, and tooth decay. However, more research is needed.

The bottom line

Research on diet soda has produced a lot of conflicting evidence.

One explanation for this conflicting information is that most of the research is observational. This means it observes trends, but there’s a lack of information about whether diet soda intake is a cause or simply associated with the true cause.

Therefore, while some of the research sounds quite alarming, more high quality experimental studies are needed before concrete conclusions can be drawn about the health effects of diet soda.

Regardless, one thing is certain: Diet soda does not add any nutritional value to your diet.

So, if you’re looking to replace regular soda in your diet, other options may be better than diet soda. Next time, try an alternative like milk, coffee, black or herbal tea, or fruit-infused water.

Source: Healthline