The Internet Calls Diet Cokes 'Fridge Cigarettes' – Here's What Drinking Them Actually Does to Your Body

At some point, the internet decided Diet Coke needed a rebrand.

It went with: ‘Fridge cigarettes.’

It’s admittedly excellent work. That cold can crack at 4pm. That little hit of relief. The insistence from devoted drinkers that they could stop whenever they wanted, while simultaneously ensuring the fridge is absolutely never allowed to run dry.

I mean, you can see it. Can't you?

But the comparison also smuggles in a pretty hefty implication: that your lunchtime fizzy drink habit might be making more than just a dent in the office recycling bin.

So, how close to smoking a cigarette is plugging a cold can of DC, really?

Let’s start with the 'addiction' element.

Diet Coke contains caffeine – around 46mg in a 330ml can in the UK. Caffeine is a psychoactive stimulant and, unlike some of the more excitable claims around artificial sweeteners, we have very good evidence that regular use can lead to physical dependence.

Stop suddenly and headaches, fatigue, irritability and difficulty concentrating can follow. Withdrawal has even been demonstrated at habitual caffeine intakes as low as around 100mg per day – just over two cans of Diet Coke.

Does that make Diet Coke ‘addictive’ in the same way cigarettes are? No, not really.

Caffeine dependence exists, of course, and a minority of users may develop problematic patterns of use, but its effects and potential for damaging and compulsive use are in an entirely different postcode to nicotine.

There’s also the habit itself to consider. That cold can. That sweet taste. That click and hiss. The afternoon pick-me-up. Pair any reliably pleasurable experience with the same time, place and emotional state often enough and you can create a powerful habit loop without needing to invoke chemical addiction at all.

But if you do find yourself in the grip of a powerful habit, what's the damage likely to be?

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This is where things start to fizz.

Diet Coke contains aspartame and acesulfame-K. In 2023, the International Agency for Research on Cancer classified aspartame as ‘possibly carcinogenic to humans’.

Case closed then?

Not really.

The research was identifying a potential hazard, not calculating the likelihood that your actual exposure would cause cancer. At the same time, the Joint FAO/WHO Expert Committee on Food Additives reviewed the evidence and found no convincing reason to lower its acceptable daily intake of 40mg of aspartame per kilogram of bodyweight.

For context, WHO estimated that a 70kg adult would need to drink roughly 9–14 cans of diet soft drink every day to exceed that limit.

That's 4.5 litres of the stuff. DAILY. Just to be in the 'risk' zone.

That doesn’t mean ‘aspartame definitely can’t cause cancer’. Those pesky scientists rarely give us the luxury of certainty. It just means the evidence for carcinogenicity is limited and current exposure levels are still considered acceptable by the bodies tasked with assessing the actual risk of these things.

Contrast that with cigarettes, where the safe level of exposure is, well, it's zero. Tobacco affects almost every organ in the body and smoking is linked to more than 20 types or subtypes of cancer.

It wouldn't be unfair to say that anyone calling these two things direct equivalents must be smoking something.

Next up: everyone influencer's new favourite area of expertise – the gut microbiome.

You’ll often hear that artificial sweeteners ‘destroy your gut bacteria’. Again, reality is considerably less rage-bait ready.

A 2022 randomised trial found that several sweeteners altered participants’ gut and oral microbiomes, but the effects differed between sweeteners and individuals. Importantly, significant negative effects were seen with saccharin and sucralose – not aspartame.

Another human trial looking specifically at realistic doses of aspartame and sucralose found no meaningful changes in the major gut bacteria measured or in short-chain fatty-acid production after two weeks.

So can sweeteners interact with your microbiome? Almost certainly.

Does that automatically mean they’re damaging it? No.

We’re still working out what many microbiome changes actually mean for long-term health. ‘It changed some bacteria’ and ‘it damaged your gut’ are not interchangeable sentences.

Sugar-free doesn’t mean tooth-friendly. Sorry.

Diet Coke contains phosphoric and citric acids, and frequent exposure to acidic fizzy drinks can erode tooth enamel even when there’s no sugar present.

That’s erosion rather than classic sugar-driven tooth decay, but your teeth probably don’t care much about the difference.

If you’re nursing a can for three hours, constantly bathing your teeth in acid, that's worth reconsidering. Drink it with meals, don’t swish it around your mouth and rinse with water afterwards.

As a nickname?

Outstanding work.

Chemically?

Absolutely not.

Diet Coke isn’t water. If you’re drinking litres of the stuff every day, losing sleep from caffeine, getting headaches whenever you stop and marinating your teeth in phosphoric acid from breakfast until bedtime, there are probably some useful changes you should look at making.

And there are legitimate scientific questions still being investigated around artificial sweeteners, the microbiome and long-term health.

But cigarettes are highly addictive products with overwhelming evidence linking them to cancer, cardiovascular disease, respiratory disease and premature death. Tobacco kills more than seven million people globally each year.

We simply don’t have remotely comparable evidence for Diet Coke.

So keep the phrase. It’s funny.

Just don’t confuse a great meme with a good risk assessment.

Andrew Tracey

With almost 18 years in the health and fitness space as a personal trainer, nutritionist, breath coach and writer, Andrew has spent nearly half of his life exploring how to help people improve their bodies and minds.    

As our fitness editor he prides himself on keeping Men’s Health at the forefront of reliable, relatable and credible fitness information, whether that’s through writing and testing thousands of workouts each year, taking deep dives into the science behind muscle building and fat loss or exploring the psychology of performance and recovery.   

Whilst constantly updating his knowledge base with seminars and courses, Andrew is a lover of the practical as much as the theory and regularly puts his training to the test tackling everything from Crossfit and strongman competitions, to ultra marathons, to multiple 24 hour workout stints and (extremely unofficial) world record attempts.   

 You can find Andrew on Instagram at @theandrew.tracey, or simply hold up a sign for ‘free pizza’ and wait for him to appear.