Not sure if you're serious or not, but in case you're unaware, there are a number of health problems[1] found from over-consumption of diet sodas (aside from anything this study has surfaced).
That article makes clear these potential risks come from observational studies, not controlled experiments.
And if consumption of diet soda correlates with other things, for example an unhealthier diet in general that the person "compensates" for by only drinking diet soda, then it would show up in an observational study even though there's no cause-and-effect.
But remember, diet soda is 99+% water. Really the only hypothetical problems with diet soda could be 1) artificial sweetener chemicals in the body triggering cancer or other ailments, and 2) artificial sweeteners triggering a glucose-like response triggering weight gain. But studies with rats indicate 1) shouldn't be an issue at anywhere near the concentrations in diet soda, and 2) seems rather far-fetched.
My man… you are arguing FOR drinking a 2L of soda a day. Take a step back, your reasons for why studies aren’t conclusive might be good, and I may not be able to refute them… but look at the ridiculousness of your position.
It's not what I do personally but I also don't judge, because scientifically, it's basically just water.
Do you have a problem with somebody drinking 2 cans' worth of LaCroix in the morning, 1 at lunch, 2 in the afternoon, and 1 at dinner? Why should that suddenly become "ridiculous" because an eyedropper amount of caramel color, caffeine, and artificial sweetener get added?
It's increasingly becoming apparent that artificial sweeteners are not so biologically inert as might be desired: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8156656/ . Do what you will with that information. I make no judgement.
There's no evidence it does so meaningfully. All that stuff about "leave a tooth in Coke overnight and it'll dissolve" is 100% urban legend.
We're eating and drinking acidic things all day long, orange juice and grapefruits and the rest. And diet soda doesn't adhere in a layer to your teeth, the way things like orange juice and sugary Coke do.
Our enamel repairs itself through our saliva. Otherwise you'd never be able to drink a lemonade or eat a grapefruit. The acidity of Coke Zero is a nonissue in the context of a normal diet.
(Not to mention that flavored carbonated waters like La Croix and Bubly are also acidic. Bubly grapefruit flavor is pH 3.86, while Coke Zero is 3.18, from a quick Google.)
I've also been drinking 2.25l of coke zero every day for 5 years and it has been a game changer for both weight and oral health. Previously i required fillings quite frequently and none over that period. Obv nobody should drink any soda if they don't have to but if replacing consumption of sugary drinks it's extremely effective for health gains. And most of the anti sugar-free soda studies are bro science.
Even so, backing things up with data and proving things via the scientific method is one of our most powerful tools we have to get people to listen to an argument. Without controlled experiments, why should anyone take your position or the opposing position on the issue?
Some people like flavored/bubbly water over plain flat water. Some people do Perrier, some do LaCroix, some do Coke Zero. All of these are essentially nutritionally identical.
Really just a question of whether you think the artificial sweetener has an adverse effect on your health, which in these quantities it doesn't seem to. And if you want caffeine -- the caffeine in a liter of Coke Zero is the same as a single cup of coffee, so this is the same as a fairly normal 2 cups of coffee per day.
But the effect is mainly in sugary drinks, not diet. In fact, a study found that diet cola decreased kidney stones, although not meaningfully, so it's probably zero effect at all [1]:
> "There was a 23% higher risk of developing kidney stones in the highest category of consumption of sugar-sweetened cola compared with the lowest category"
> "Artificially sweetened sodas were marginally associated with kidney stones, with an inverse relation for colas and a direct relation for noncolas."
So no worries about your Coke Zero giving you kidney stones. The culprit seems to be the fructose, rather, which Coke Zero doesn't contain:
> "Higher consumption of sugar-sweetened soda was associated with a higher incidence of kidney stones, which may be because of the fructose content. Fructose has been shown to increase the urinary excretion of calcium, oxalate, and uric acid, thus increasing the risk of stones."
The large drink size at a major gas station chain around here is about 1.8 liters. It's a popular size. Some people may drink one over multiple days, but that's not the norm. And that's not the largest size any gas stations around here have.
Some "medium" sodas at fast food joints are over a liter, these days.
People who drink a lot of soda, in the US, really DRINK A LOT OF SODA.
Consider also that it's been the norm for years, in the US, to have free refills on soda at restaurants (with waiters eagerly topping them off constantly) and that many fast food places have self-serve soda that's either explicitly or de facto unlimited refill, if you go inside to eat rather than using the drive-through.
I buy my 2Ls for $1 on sale. $30 a month for pop is very affordable. RE your health; the components of diet pop are some of the most studied and consumed chemicals and sweeteners on the planet. The worst thing it’ll do is possibly wear your tooth enamel. So, I’d say it’s fine for their health and wallet.
[1] https://www.uclahealth.org/news/observational-studies-shed-l....