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What's in diet soda? -

To begin with, diet soda is usually made up of carbonated water, artificial or natural sweeteners, colors, flavors, and other food additives.

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Artificial sweeteners -

But how can these drinks be so sweet without having any sugar in them whatsoever? The artificial sweeteners used (such as aspartame, saccharin, sucralose, or a herbal sweetener like stevia) are around 200 to 1,300 times sweeter than sugar.

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Liquid consumption for weight loss -

As these drinks usually have little or no calories, they could be assumed to aid weight loss, just like water does. But the research suggests otherwise.

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Aspartame -

Aspartame is one of the most common artificial sweeteners found in countless products throughout the US and the rest of the world. From Diet Coke to Wrigley's Extra chewing gum, it's fairly ubiquitous in processed foods and drinks. The health risks of consuming aspartame have long been a concern, but commercial interests have hampered research on the topic for many years. In 2024, however, the cancer research branch of the World Health Organization came to the worrying conclusion that aspartame is a possible carcinogen, meaning it may cause cancer. When the WHO has raised concerns about the safety of certain substances in the past, it has led to immense pressure from consumers for producers to change their recipes and find safer alternatives—a process that is extremely costly. 

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Obesity and metabolic syndrome -

Numerous observational studies find that drinking many of these drinks, which are high in artificial sweeteners, is associated with an increased risk of obesity and metabolic syndrome.

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Altering taste receptors -

Scientists say that artificial sweeteners stimulate hunger and alter taste receptors in the brain.

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An enabler -

Some studies suggest that it’s not the actual diet soda that is the issue. It’s the habit that they enable. It’s people's dietary habits when drinking these drinks.

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One research paper proved it to be effective for weight loss -

However, in one study, two groups drank either 24 ounces (710 ml) of water or diet soda per day, and after one year, the group that drank diet soda lost an average of 13.7 pounds (6.21 kg), and the group that drank water only lost 5.5 pounds (2.5 kg).

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Bias in scientific community -

To add to the confusion, there is reported bias in the scientific community. Research published by the soda industry is usually favorable compared to research that is not connected to the industry.

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Type 2 diabetes -

Some research found that drinking just one of these diet drinks a day increased the chances of developing type 2 diabetes by 8-13%.

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It's less risky than normal soda in developing type 2 diabetes -

However, multiple studies have found that with women, the risk of developing type 2 diabetes when regularly consuming diet drinks is around half that of people who consume the standard soda.

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High blood pressure -

Astonishingly, a review of four studies found that for the consumption of each diet drink (single portion) consumed a day, people’s risk of high blood pressure was increased by 9%.

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Research issues -

Research in this subject is problematic because of industrial influences, but it’s also because of the study’s design.

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One issue with design of research -

For example, when scientists are monitoring people’s health when consuming these drinks, it’s complicated to separate where the drink primarily causes weight gain and other health issues, or whether it is the summation of many parts of the subject's life (i.e. they drink diet drinks but also don’t exercise, eat poorly, smoke, etc.).

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Kidney disease -

Regarding other health issues other than weight gain, diabetes, and heart disease, the research is more conclusive. The verdict is in on its effect on kidney disease.

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Kidney disease -

Drinking more than seven glasses of diet soda a day doubles your chance of developing kidney disease.

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Phosphorus -

It’s suggested that the phosphorus content of soda causes an acid load on the kidneys.

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The cure and the cause -

Interestingly, one study found that drinking diet soda increased the risk of developing kidney stones. Another found that the high citrate and malate content help treat it for people with low urine pH and uric acid stones.

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Cause of preterm delivery -

A study conducted in Norway found an 11% increase in preterm delivery when pregnant women consumed artificially sweetened drinks.

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Supported findings -

A Danish study supported this claim, finding that pregnant women who consumed just one artificially sweetened soft drink per day were almost one and half times more likely to deliver preterm (before 37 weeks of pregnancy, as opposed to 40).

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It causes preterm delivery, but it's unclear as to why -

It’s important to note that these studies were only observational. They do not explain why consuming artificially sweetened soft drinks is linked with preterm delivery regarding childbirth, and therefore there is no conclusive evidence that it couldn’t be something else.

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Childhood obesity -

Another study found that pregnant women consuming these kinds of drinks daily significantly increase the chances of childhood obesity in their children.

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It burns fat around the liver -

It’s not all bad. Some studies have found that replacing sugary soda drinks with diet soda can decrease fat around the liver.

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Low bone mineral density -

One study found that the caffeine and phosphorus in diet soda drinks, which can be found in many other beverages and average soda drinks, is associated with low bone mineral density in women but not in men. It’s suggested that phosphorus interferes with calcium absorption.

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It's bad for oral hygiene -

The acids in diet soda cause tooth decay and enamel erosion.

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Overall, it's not good for you -

However, one thing is certain: it does not add anything of significant nutritional value to your diet.

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Long-term health effects aren't known yet -

The truth is that it is a very new form of drink. Gut feeling suggests that drinks this sweet and tasty cannot be good for you. However, time will tell.

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A word of advice -

If you are in any way concerned for your health, you’re better off replacing these kinds of drinks with something else or just drinking water. 

Sources: (Healthline) (CJASN) (Nursing) (BMJ) (Obesity (Silver Spring)) (Advances in Nutrition) 

See also: How to actually cut sugar out of your diet

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