How do you get to the point of debating the difference between soda vs. diet soda, as if it's a must-have treat and you are "simply" choosing the lesser of two evils? All soda is UNEQUIVOCALLY bad for one's health! You're drinking a cocktail of chemicals that has no nutritional value, and designed to be addictive. Artificial sweeteners are a gimmick to allow us to recuse ourselves from the innate knowledge of what it is healthy. Selecting a supposedly "healthier alternative" is nothing more than a way to grant ourselves asylum from being personally responsible for our choices. We pretend that our "science" is universally proven evidence backed by chemistry and physics, vs. the truth: it's a manmade lie which no enlightened species would tout as being scientifically valid.
The same mental masturbatuion occurs with vaping. "Vaping is better than smoking!" As if inhaling any mind-altering drug is necessary to "get by", and so it must surely be "better" to attach oneself to the "least worst option", rather than kicking the habit entirely. If vaping is "better" than smoking, what is better than vaping? Oh right, not inhaling anything other than the air we evolved to breathe. Your body wasn't made to inhale chemicals not produced in nature; it was also not made to drink soda. The fact that you don't die instantly from consuming such products does not mean they are not harmful.
The excuses many people make regarding their health is... I'm going to call it what it is: completely and utterly _PATHETIC_. As a species we pretend we are intelligent, but a vast percentage (90-95%?) of the population can't even overcome the most primal appetite for fats, sweets and drugs. Our species will never be capable of rightfully calling itself "enlightened" until we drop all desires for this kind of bullshit. If you're playing mind games with yourself to allow you to "cheat just a little" by consuming unhealthy products, while falsely duping yourself into believing your decisions somehow result in an overall net positive "compared to the (unnecessary) alternatives", you're deluding yourself.
Advice to all alien civilizations: avoid us at all costs. Making contact with us cannot possibly be beneficial to you. We'll either bomb you out of fear and ignorance, or bombard you with our capitalist bullshit in order to pull you into our way of living that will ultimately destroy you from the inside out.
What makes this truly disgusting is that people who choose to destroy their bodies - by drinking diet soda, vaping, or eating junk food - are in fact aware that they are lying to themselves. You know that you are making the wrong choices, but opt for the fallacy that somehow you are not in control. Nobody really believes the marketing companies are pushing out. People are just looking for someone else to give them permission to be unhealthy, desperately listening for someone to tell them what they want to hear. People know they are too weak to have self-control, and are looking for a voice to be their scapegoat.
tldr; Diet soda is not "better" than soda laden with unadulterated sugar. It is simply worse than water, and the fluids you would get from fruits, vegetables, and free-range animals and fish. Allow your brain's thought processes to align with your species' natural evolution. Stop using product manufacturers' claims as a scapegoat. Think for yourself, and don't make excuses.
Edit: To those downvoting: do you downvote because my post is too long and you declined to actually read it, or do you refute the facts? I am normally abrasive in general, but what I've said here really is true. Anyone who reads the whole thing, and still downvotes, is someone with their head in the sand. You can be part of the 90-95% of morons I mentioned earlier. Be the reason our species is doomed, for all I care.