It’s calorie- and sugar-free and seems like the perfect fix for everyday sweet cravings – but is diet soda as harmless as it appears? The idea that diet soda is harmless needs to go. Sure, it doesn’t contain sugar or calories, but that doesn’t make it a safe alternative.
Behind the “guilt-free” label lies a cocktail of artificial ingredients that may still increase your risk of developing diabetes – just through a different door. So, can diet soda cause diabetes? Likely, and here’s why:
What’s in Diet Soda, Really?
Non-Nutritive and Nutritive Sweeteners – The Difference
What exactly gives diet soda its sweetness – and how does it manage to dodge the calorie count on the label? The answer: sugar substitutes.
Sugar substitutes are categorised into two groups: nutritive and non-nutritive sweeteners. Nutritive sweeteners include xylitol and sorbitol, often used to prevent tooth decay and cavities. These sweeteners generally have the same number of calories as sugar, so there’s no caloric benefit when substituting them for regular sugar.
Non-nutritive sweeteners are either artificially created or derived from plants. Examples include saccharin, aspartame, sucralose, ACE-K, monk fruit extract, and stevia. Diet Coke and Pepsi use aspartame, also known as NutraSweet. Coke Zero, Pepsi Max, and sugar-free Red Bull all use aspartame and ACE-K, sometimes labelled as acesulfame potassium.
Red Bull Zero simply adds a third sweetener, sucralose – also known as Splenda – to the sugar-free version. These non-nutritive sweeteners have few to no calories and are far sweeter than regular sugar. Because of this intensity, only small amounts are used.
What’s the Big Deal Then?
Even with the reduction in sugar and calories, these ‘diet’ drinks can still contribute to the development of diabetes. Several studies have highlighted that substituting sugar correlates with metabolic syndrome. It’s important to note, however, that these studies found a correlation, not causation.
PLOS Medicine published a study in 2022 emphasising the association between artificial sweeteners and cancer. The study examined over 100,000 people in France who consumed artificial sweeteners. It also accounted for other variables such as age, smoking, drinking habits, and lifestyle.
These individuals were compared with those who did not consume artificial sweeteners. The study found that artificial sweeteners – particularly aspartame and ACE-K – were associated with a 13% increased risk of cancer. While this highlights a concerning link, further research is needed to prove causation.
The Science Behind the Diabetes Link
There’s an emerging connection between diet soda and the development of various metabolic issues. Artificial sweeteners stimulate sweet taste receptors, which trigger insulin responses – even without real sugar.
Over time, this may confuse the body’s ability to regulate blood sugar, potentially leading to insulin resistance. A 2009 study in Diabetes Care, which tracked over 6,000 participants, found that those who drank diet soda daily had a 67% higher risk of developing type 2 diabetes compared to non-consumers.
How Artificial Sweeteners Affect Your Body
Let’s say you’re drinking Diet Pepsi or Pepsi Max – how does it affect your body? Firstly, your tongue detects sweetness from the artificial sweetener. The taste buds then send a signal to the brain – specifically the hypothalamus. This part of the brain is tricked into thinking that it’s real sugar due to the sweet taste.
The hypothalamus then signals the pancreas to metabolise the sugar. The pancreas begins secreting insulin, but the sugar never actually arrives. So, what happens to the excess insulin? Unfortunately, the pancreas doesn’t reabsorb it. Instead, it sends a signal to the brain to stimulate appetite. You feel hungrier, and eat more – so the insulin already released can be “used”.
An article in The American Journal of Clinical Nutrition reported on a randomised study conducted over six months with four groups. Each group followed a standard diet, but one drank one litre of sugared soda per day, another drank one litre of diet soda, the third drank milk, and the fourth drank water.
The group who drank sugared soda gained around 22 pounds after six months. The group who drank diet soda also gained weight – but only 3.5 pounds. The group who drank milk maintained their weight, while the group who drank water lost approximately 4.5 pounds.
Is It Worse Than Regular Soda?
The short answer is no. The long answer? While the diet soda group only gained 3.5 pounds compared to the group that gained 22 – even though both consumed the same number of calories through food – it’s clear there’s nothing “diet” about diet soda.
So why did the milk group maintain their weight, even though milk contains as many calories as sugared soda? Simple. The fat and lactose in milk do not trigger the same insulin response as artificial sweeteners.
Other Hidden Risks
There are other reasons why the artificial sweeteners in sodas are generally unhealthy. For instance, diet soda doesn’t contain any fibre. And generally speaking, the more diet soda you drink, the less fibre you tend to consume – particularly insoluble fibre.
Why? Because the cravings triggered by insulin spikes are usually for carbs and sugar, not fibre-rich foods like oats and vegetables. This may result in harmful changes to the gut microbiome. In such cases, harmful bacteria overtake the gut, eroding the mucin layer of the gut lining and causing microscopic leaks. This allows pro-inflammatory chemicals to seep into the bloodstream, promoting fat storage and metabolic dysfunction.
Additionally, intestinal bacteria influence the brain’s perception of hunger and satiety. A study published in 2013 in PLOS ONE titled A Novel Regulatory Function of Sweet Taste-Sensing Receptor in Adipogenic Differentiation of 3T3-L1 Cells suggested that some sweeteners may have insulin-like effects, contributing to fat storage.
Some studies also found that certain people may become addicted to artificial sweeteners. Animal research suggests that artificial sweeteners and real sugar activate similar brain pathways. Aspartame, in particular, showed significant negative effects on oxidative stress and inflammation in animal models.
What the Experts Say
The International Journal of Obesity published a 2017 study in which diet soda drinkers were switched to water. Over 18 months, that group lost an average of six pounds. Both water and diet soda have zero calories – so why the difference? It comes down to how each beverage affects the body’s insulin response.
Health concerns like oxidative stress and inflammation – as mentioned earlier – were largely dismissed by the European Food Safety Authority (EFSA). The agency ignored 73 studies showing the harmful effects of aspartame, while accepting 84 studies claiming no adverse effects.
Healthier Alternatives to Try
A study by the American Diabetes Association looked at 17 morbidly obese adults without diabetes. Researchers compared insulin responses between diet sodas and seltzer (carbonated water without sweeteners). The insulin response to diet soda was found to be 20% higher than to seltzer. If it’s a fizz you’re after, try kombucha! You can even make it yourself.
If you want to know more about living a more healthy livestyle, read about the link between your gut health and immunity.
Can Diet Soda Cause Diabetes? Rethink “Guilt-Free”
Ultimately, artificial sweeteners are a better choice than sugared soda – but still much worse than water. This is especially true in relation to insulin resistance, obesity, and diabetes. Current studies do not conclusively prove that artificial sweeteners cause metabolic syndrome or cancer, but the correlations are difficult to ignore – particularly as rates of obesity and metabolic syndrome continue to rise, despite decreasing sugar consumption.
At the end of the day, your best bet is water. But if that doesn’t satisfy your fizzy craving, diet or zero-sugar sodas are still infinitely better than the sugared ones.
