alt Hacker NewsIt's harm reduction.
If you are going to be drinking 6 cans of soda a day, then diet soda is going to be better for you based on all available evidence today. By a large margin.
Drinking zero cans of soda is quite obviously better than either of those options.
Those who tend to indulge in large amounts of these substances typically have other unhealthy eating (and other) habits so good luck figuring out causation here.
I lost 100lbs coming from close to morbid obesity. Diet soda is the single vice I refuse to give up for mental health reasons. Of all the vices (eating, drinking, substances, etc.) I had before, this seems like the least concerning. Some people don't need that mental blowoff valve, but if I'm going to maintain the rest of my healthy habits I've found I require such a thing.
It is easy to get off soda once you get off it already and drink water. As when you do eventually get back to it and go "Maybe I'll have a coke" what you will find will be severely disappointing. Mouthfeel is terrible. Every sip you try and get that taste in your imagination of what you think is coke but you end up just tasting fructose concoction and carbonation. Makes you feel dehydrated after, like you have to chug a pint of water just to make your saliva not so viscous. The only sugary drink I tolerate now is lemonade I make myself. And I'm drinking it partially for carb load.
So really, get off the soda. It isn't even a great mental reward. Have a piece of chocolate instead. There are gut health benefits with chocolate.