Diet Fizzy Drinks - Horrendous or a bit bad?

So I know that water is great, and I’m really trying to replace fizzy drinks with it. But I have a massive soft spot for diet coke and diet lemonade, both zero calories so what’s the problem with it? Doors anyone have a medical, or otherwise, explanation about why is an issue drinking buckets of it?

I’ve had this exact conversation with my sister who is a Dr of nutrition (so pretty qualified!)

Her take on it is pretty much what you’d like to hope - water is obviously best but if you’re putting less sugar in your body it can only be a good thing. She rates these sorts of drinks higher than sugary squash too which people often think is better.

You still have to be careful with your teeth though as the carbon dioxide will still cause problems with your enamel.


In terms of weight loss? Nothing at all…

Medical? No idea…

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Drinking buckets of anything isn’t a good idea. Some diet drinks come with things like caffeine and ginseng added (Pepsi Max). Just like drinking too much coffee can affect you there will be some effects on your body. Though as @maxnas points out its not going to have any effect on weight loss/gain.

Some people report that consuming diet coke stimulates their appetite. Not found that myself, suspect it may be a learned response where they have previously consumed food with the fizzy drinks.

@IrishPete makes the point about it affecting your teeth. As I understand it the phosphoric acid and other things they put in at are the damaging part. The Carbon Dioxide isn’t that particularly. i.e. fizzy water isn’t bad for your teeth.

I’ve pretty much replaced diet coke with fizzy water.


Yeah I’ve heard a few anecdotal instances about people finding that carbonated water etc blunting their hunger somewhat… no idea if there’s any data to back it up, if it’s a psychological thing or an actual physiology thing, but i’ve heard it quite a lot recently

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spot on. I ruined my teeth with Diet Coke when I was driving here there and everywhere. Thought I was doing ‘the right thing’ but dentist explained that it was more about the phosphoric acid than the sugar.

@baxter you are obviously bang on the money with the ‘water first’ philosophy, and you are right to be sceptical of artificial sweeteners (AS), the ones that are man-made chemical AS’s are where the real problems can lie (Acesulfame K, Aspartame, Sucralose), particularly in children where headaches and hyperactivity have followed their consumption.

For adults the potential problems seem to be increasing based on our growing knowledge of the microbiota aka the bacteria in our gut. Despite the general consensus being that AS’s are safe in adults, the supporting evidence is scarce, and sadly the absence of evidence isn’t evidence of absence.

According to (one of the most respected journals around) the main concern is more to do with AS’s impact on glucose intolerance, through induction of compositional and functional alterations to the intestinal microbiota. Basically, the AS’s appear to change the type and expression of gut bacteria we have which may reduce our ability to utilise glucose, in turn increasing risk of developing conditions such as diabetes.

More empirically too, the mouth has sweetness receptors which may be tricked into thinking the body is receiving carbohydrate (and energy) when we consume sweeteners…only to receive no energy at all. By definition artificial sweeteners are not natural so where possible are best avoided. The natural sweetners such as Stevia and Monk fruit are a better option BUT may still ‘throw the body off’ somewhat with their sweetness and yet non-calorific nature.

So the calories saved when consuming artificial sweeteners may be off-set by the negative effects on our microbiota, which some consider so important that it warrants the label ‘our second genome’. Best to look after it then.

Great question!


Even better answer!


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Unless I’m missing something new, I’m unaware of any solid & replicated evidence of this mate, only personal anecdotes mostly from people with shitty diets (correlation not causation) & studies on rats,

but the mass of human research has never been able to replicate these apparent results even though aspartame is one of the most researched compounds ever… I’m unaware of any reason to suggest its unsafe for human consumption in reasonable doses, and the vast majority of stories seem to be claimed through conspiracy and quack sources.

Unless theres new data/research I’m unaware of?

Happy to be wrong and learn something new :+1::blush:

PS - dont get me wrong btw, im not pro or against… I actually used to be very unfoundedly biased against it until I studied the research

@maxnas thanks for diplomatically pointing that out…I have to agree with you. Although empirical evidence exists that is not evidence of causation and it was a little out of turn for me to assert that point. Trigger happy when on a roll writing!

I am actually neither for nor against AS’s as a whole, when weight loss is a primary focus they can have their merits to induce a calorie deficit, in the short term at least. Whereas those with a relatively normal BMI may benefit from sticking to regular sugar sweetened beverages etc and just consume it in, wait for it…moderation! haha.

Again, thanks for pointing this out, keeps us honest and prevents laziness (on my part).

For the sake of clarity re: the points on AS’s and onset of glucose intolerance and Diabetes, here is a Meta-analysis giving a nice consensus of AS’s and sugar in the onset of Diabetes >>>

And the article supporting the impact of AS’s on our microbiota and the effect on glucose intolerance >>>

Thanks @maxnas


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Hey my man, I genuinely just thought I may be missing something new or overlooking things.

Probably just like yourself, I can completely geek out & talk at insane depths about this stuff all day long just for fun. lol

Although I try not to go to deep unless it’s with other nutrition geeks as the techno-bable tends to go over peoples heads, especially since most don’t need to know this stuff to make use of the basics for weight loss… it sometimes does the opposite and causes further confusion.

I see it as my job to practically live on pubmed & research reviews, use myself and clients as human guinea pig, keep up to date with all the industry practical and anecdotal research and spend all my free/fun time on lectures/webinars/further education etc and then break this stuff down into absorbable chunks of relevant information and hand deliver it to people who need it, and no more than they need at any given time

But yeah… this is fun for me lol

I know other people think it’s really weird :smile:


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A man after my own heart mate :slight_smile: I wish the evidence was a little more solid on AS’s…35 ish years since Aspartame came into the food chain on a routine basis and still struggling to come to a conclusion other than ‘more research needs to be done in this area’…

But hey, perhaps the fact we can’t find any negative evidence is a sign it doesn’t exist. Either that or we aren’t looking in the right places OR the time for the negative effects to manifest are too far down the line and we are yet to see it! :confused:

Look forward to chatting more with you @maxnas



Woah woah woah… what’s going on? This is an Internet forum and two people had slightly differing opinions. I think you’ll both find that the accepted protocol is so completely roast each other and let the thread descend into anarchy.

@maxnas and @TomIrvNutr23 his unusual behaviour is freaking me out.


I think you’ve misread our posts mate… we’ve both shared helpful info and pretty much agreed on the same points :blush:

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Hahaha, nothin but love on this thread @IrishPete

I get the joke now :joy::joy::joy:

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So here’s my take: in 3 weeks I have lost half a stone. No effort, just dropped off.

I was drinking 2 litres of coke a day. The full on, red label, fat coke. Yes, that bad. I am down to about a litre a day now, but it’s been coke zero. In those 3 weeks, I still went to the chip shop (shoot me now), ate a lot of other ‘bad food’. I always maintained I never ate that much in a day really, and I still do.

But after giving up cigarettes 4 months ago, next on my list was the pop. When I weighed in at 19.5 stone 3 weeks ago, it shocked me into signing up to ManVsFat & I dropped the coke.

That’s why I am so desperate to start playing football again as I’m sure the weight will carry on dropping off. Last night I did a 5 mile walk with the dog in torrential rain, took us about 90 minutes.

So I am currently all for diet fizzy drinks, but am slowing weaning myself off them.


So just to clarify for you mate so you understand whats going on behind the curtain

You’ve swapped 2 litres of high calorie drinks for 1 litre of a lower calorie option, meaning you’ve reduced your overall energy/calorie intake = weightloss

Instead of doing it through tracking, you’ve defaulted the same science by addressing a simple habit/environmental change, which is great, well done

Just keep in mind WHY its working and dont get romantic about the coke itself… its what its doing thats making the difference :blush::+1:

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I’m fully aware why I have lost weight so far, I was just saying that for me, right now, ‘a bit bad’ is a good thing. Hence ‘currently all for diet fizzy drinks, but am slowing weaning myself off them.’

I get that your game is ahead of my game, that you have abs, have some sort of fitness website. Well done, I’m proud of you. Things take time. I set a goal of 5 stone weight loss. I was happy to have done 10% of that in 3 weeks. The treadmill arrives this weekend for one of the spare rooms. So spare a thought for those of us who are just starting out after years of neglect. :slight_smile:

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