How your body reacts when you give up diet fizzy drinks

You’d be hard-pressed to find a health professional that recommends drinking fizzy beverages. Not only is the acidity bad for your teeth, but the sugar can lead to weight gain and, in severe cases, diabetes.

Diet versions aren’t much better, unfortunately, especially as aspartame, a common sugar substitute, has been marked out as a potential carcinogen by the World Health Organisation (WHO).

A pair of fizzy drinks - 112233 via Getty Images

“After reviewing the available scientific literature, both evaluations noted limitations in the available evidence for cancer (and other health effects),” it said in July 2023.

“IARC classified aspartame as possibly carcinogenic to humans (Group 2B) on the basis of limited evidence for cancer in humans (specifically, for hepatocellular carcinoma, which is a type of liver cancer).”

Although this isn’t great news for aspartame, it added: “There was also limited evidence for cancer in experimental animals and limited evidence related to the possible mechanisms for causing cancer.

“JECFA concluded that the data evaluated indicated no sufficient reason to change the previously established acceptable daily intake (ADI) of 0–40 mg/kg body weight for aspartame.

“The committee therefore reaffirmed that it is safe for a person to consume within this limit per day.”

So while it’s not absolutely certain that aspartame has cancer-causing properties, keeping within the recommended daily intake is recommended. Cutting it out altogether may not make a difference, but some would rather be safe than sorry.

Aspartame is a common ingredient in other sugar-free treats as well, such as various chewing gums, isotonic sports drinks, and ready-made coffees, so bear that in mind.

Beyond the potential carcinogenic element, there are other effects that sweeteners have on the body that you likely won’t miss.

Let’s take a look at what happens to your body when you switch from drinking diet pop regularly to completely abstaining.

You’ll think more clearly

Artificial sweeteners have been shown to have an effect on brain activity.

A review in the European Journal of Clinical Nutrition said that those effects can trigger chemical imbalances that lead to headaches, anxiety and insomnia.

Rat-based lab tests found that diet soda damaged their brains’ nerve endings and had an impact on their motor skills.

Food will seem more flavoursome

Your taste buds are very stimulated by sweeteners, especially given that aspartame is as much as 200 times sweeter than sugar.

This sweetness has been shown to confuse your brain’s taste processors, making you more likely to crave sweet flavours whilst also dulling your tongue’s ability to taste things properly.

However, claims around aspartame’s effects on taste receptors are still heavily contested, and we’re still waiting for conclusive research to get to the bottom of things.

You may find it easier to lose weight

While some mistakenly believe that diet soda will help them to lose weight, it’s important to remember that diet soda only cuts the calories you would consume with a regular fizzy drink.

So while they may be less calorific than regular fizzy pop, they won’t assist with shedding calories elsewhere in your diet.

Some research has suggested that regular diet drink consumption actually had links to weight gain.

A study from 2005 found that daily diet soda consumption correlated with a 65% increase in a person’s likelihood of becoming overweight within a decade.

But, let’s face it, someone who’s drinking diet soda every day is likely to be making other poor dietary choices on the regular.

At any rate, substituting fizzy drinks for water is a good idea for cutting out calories and sweeteners, and it’s a good way to help you to feel full between meals without adding more calories to your diet.

Your bones may strengthen-up

A study from 2019 found a correlation between increased risks of bone fractures in post-menopausal women who drank more than two servings of diet soda each day.

While these results are interesting, it’s important to also note that menopause has been shown to decrease bone density as a result of lowered oestrogen levels.

Ageing generally leads to weaker bones for both men and women, too.

So yeah, maybe take that one with a pinch of salt.

A woman undergoing a kidney ultrasound scan - PonyWang via Getty Images

You may experience improved kidney function

The National Kidney Foundation in the US noted that diet pop had also been correlated with damaged kidney function over time.

“Kidney function declined over two decades in women who drank several diet sodas a day, according to researchers from the prestigious Nurses' Health Study,” it said.

“In fact, compared with women who did not drink diet soda, soda-drinking women had a 30% greater reduction in kidney function in 20 years.”

Your kidneys are responsible for filtering excess fluids and other waste out of our blood, so perhaps the sweeteners and other chemicals found in diet sodas wear them down over time.

Cutting them out and giving your kidneys plenty of fresh water is therefore likely to be a good idea..

You may lower your risk of developing diabetes

Some studies have found that diet sodas may cause your insulin levels to spike, especially if had before or alongside a meal.

High levels of insulin can lead to insulin resistance in our bodies, resulting in type 2 diabetes. Insulin is responsible for managing your blood’s sugar levels, generally by triggering cells to absorb and store it as fat.

When your body stops responding properly to insulin, your body won’t be able to manage your blood’s glucose levels as effectively, leading to a whole host of health problems that can include blindness and amputated limbs.

Keeping your sugar consumption down is a good idea in general, but be wary that sugar-free food and drink may still be causing insulin spikes in your bloodstream.