They use different formulas. Diet coke is an older formula, and has a distinct flavor from regular coke. Coke Zero tastes like regular coke.

Both have zero calories, and work for calorie cutting.

Upvote for using “pop”. But the other answers are right. “Diet” pop uses aspartame. “Zero” pops use the newer generations of artificial sweeteners.

Diet coke only uses aspartame while coke zero uses both aspartame and another artificial sweetener called Ace-K. Some people have higher sensitivity to aspartame, so coke zero tastes less chemically.

Carbonated water, friend. Leave the fake sweeteners on the shelf.

Diet Coke doesn't taste like Coke, so they released Coke Zero, which tastes more like Coke, but is still sugar free. I also heard they struggled to get men to buy diet coke as it had been marketed to women for years, so it was a fresh start for their marketing department.

Coke Zero tastes three times better. On ice in a glass it's amazingly close to real coke, while DC still retains that metallic taste. And, jeebus, out of the can, I find Diet Coke virtually undrinkable.

Oddly I notice much less of a difference between diet Dr Pepper and Dr Pepper zero than between Diet Coke and Coke Zero. When the grocery store has multiple-buys-necessary sales, I will often get both of them among the selection. I probably couldn’t tell you which was which if you gave me a taste test.

"Zero" sodas try to more accurately mimic the flavor of the original. "Diet" sodas have their own unique flavor.

At least in terms of marketing - Diet Coke has its own cult following. They like the taste. Coke isn't gonna change that. On the other hand Zero is targeted more for people who want the original Coke taste without sugar/calories. 

Diet Coke uses more aspartame, which tastes a bit lighter. Coca-Cola Zero Sugar uses aspartame too, but combines it with acesulfame potassium, creating a more robust flavor that's closer to actual sugar.

You know, I actually dont really taste a difference between diet coke and coke zero, but I prefer them both over regular coke - I dont like the feeling of the sugary syrup on my teeth. And interesting that you prefer fountain coke over store-bought, I always find them a little too flat.

It’s a synergistic effect; ace-K wouldn’t taste right by itself. Aspartame has a delayed sweetness compared to sugar, but ace-K has an immediate sweetness that tails off quickly. When you combine the two, they have a rounded sweetness more similar to sugar.

Flavor. Diet coke is flavored differently. Coke 0 is flavored like regular coke

When Diet Coke first came out, the technology didn't exist to make it artificial sweeteners taste like sugar. Therefore, they couldn't make it taste like Coke. Instead, they came out with a completely new flavor that slightly resembled Coke but worked better with the artificial sweetener flavor.

Over time, technology improved, and we now have artificial sweeteners that resemble real sugar much better. Coke Zero was developed because its flavor more closely matches that of regular Coke. Diet Coke still exists because there are many people who prefer its flavor.

The artificial sweeteners used in Diet Coke and Coke Zero depend on the market. Currently, Diet Coke uses mostly aspartame with some cyclamates and acesulfame potassium, while Coke Zero uses mostly acesulfame potassium with some aspartame.

On a related note, the ill-fated New Coke of the 1980s was loosely based on the flavor of Diet Coke, just with sugar instead of artificial sweeteners.

Thanks. IIRC they both have natural flavors though. I meant to say artificial sweeteners.

Short answer, is prior to Coke Zero, diet Coke was seen as a "girly" drink. Coke wanted a no-calorie soda to market towards men. So, different formula, in a different can, with more manly colors (black and red as opposed to silver) and you have yourself a new soda.

Coke Zero is supposed to taste more like real Coke than diet Coke, but since diet has been around for so long and so many people like it, Coke wasn't about to have another "new Coke" fiasco by replacing a popular soda with a new formula.

Back in the 80s when they first got artificial sweetener available and started making diet soda, they noticed that coke didn't taste very good when using the usual recipe and replacing the sugar with sweetener.

They solved this by formulating an entirely new cola recipe that tasted better with artificial sweetener, which was released as diet coke. Pepsi was winning the soda wars at the time, but this new soda was so popular that they actually saw it as a solution. They released "new coke" using the diet coke recipe and real sugar.

So basically, diet coke is the new coke recipe with artificial sweetener. Coke zero is the original coke recipe with a different type of artificial sweetener.

Diet Coke is marketed towards women (with silver, white and sometimes red colours) and comes in bottles and cans

Coke Zero is marketed towards men (with black and red colours on the bottles)

Coke Zero is slightly "sweeter" tasting than diet coke, I've had enough of both over the years to be able to tell the difference

I mean I think Coke Zero was marketed towards people who liked Coke but not Diet Coke and wanted a sugar free option.

I can't stand diet coke or coke Zero but I'll take a Pepsi Max over a Pepsi everytime.

They have different flavor. Coke Zero tastes like regular coke, while diet coke is more obviously a different product

I expect that diet coke was made in era when trying to match the flavor of regular coke would be close but wrong, so it had to be its own thing. (Diet Coke is very old, while Coke Zero is a relatively recent product)

Different sweeteners. Coke Zero tastes very similar to sugar coke (at least to me and I'm in Australia so we use cane sugar, never tried corn syrup Coke).

Diet Coke tastes like filtered swamp water, but enough people seem to like it that it's worth them keeping it around still.

Coke has a blurb about this on their website: https://www.coca-cola.com/us/en/offerings/faq/whats-the-difference-between-coca-cola-zero-sugar-and-diet-coke

They use different artificial sweeteners and serve two different market segments.

In my personal opinion Coke Zero tastes like Coke (once you acclimate to the sweetener taste) and Diet Coke tastes like Diet Coke.

"Zero" is marketed to men, "Diet" is marketed to women.

I'm serious.

Diet was made first as a sugar free alternative but it has that distinct "diet" taste that's different from the regular version. The Zero version was made years later as we developed better sugar free sweeteners and tastes closer to the original version. So the Zero version is the sugar free soda that actually tastes like the real thing.

The reason for this is due to the New Coke fiasco where they changed the recipe of Coca-Cola and customers were unhappy if not downright outraged. Instead of just changing the recipe they released a new product hoping that customers would eventually switch over (The original colour scheme for Coke Zero looks identical to Diet Coke as it was thought to eventually replace it).

Coke Zero in the beginning didn't do that well, Diet Cola had a loyal customer-base and the non-diet customers had a pretty negative view of diet sodas due to the associated diet taste. Lots of marketing as well as the passage of time and people are increasingly adopting the Zero version over both the Diet versions as well as the original version.

Zero versions, especially with clear soda for some reason, taste far more like the original. I love me some sprite zero lol.

Diet pop has a diet taste that some people love but I can't stand lol.

The sweeteners and formulations are slightly different. It's strictly down to taste. The names themselves are marketing.

Diet lighter taster, Zero closer to the original version.

I like Zero Sugar Coke but did not like original Coke Zero from 2005 (which they stopped making in 2017), the newer (current) version tastes better.

diet Coke is it's own entity, was not meant to taste like anything else Coca-Cola had made, so that is timeless to me, like TaB was.

But I prefer Zero Sugar Coke if I had to chose between the two variants.

Coke zero 100 times out of 100

It tastes more like Coke

I can’t stand Diet Coke (or Diet Pepsi, or most “diet” drinks).

But Coke Zero is incredibly decent — especially with food. It’s not quite as good as full sugar Coke, but it’s shockingly good for a no-calorie soda.

Coke Zero is friggin delicious

The new Coke Zero Sugar is a revelation and I love it so much.

As someone who LOVES Diet Dr. Pepper, I can’t do Dr. Pepper Zero. It’s way too flat…not nearly enough carbonation.

This is 100% true imho (excluding the new blueberry and strawberry flavors), but my paranoid ass will still ALWAYS choose Diet Coke over Coke Zero when it comes to fountain drinks just so I Know For Sure that it’s NOT the bubbly corn syrup juice

While I agree that Coke Zero technically tastes better, I still prefer the chemical laden liquid that is my beloved Diet Coke

all these goddamn cokes, i don't know the difference. all i know is that if it's sugar free and tastes like cola, i want it in me

I already had some opinions on this but I recently learned that Diet Coke has 12 mg more caffeine per can than Coke Zero! I have priorities, Diet Coke 4EVA

pepsi max is a million times better than the sugary sweet crap that is regular pepsi.

Zero sugar is supposed to taste more like normal Pepsi

I'm more of a diet fan. I find diet much more sweet although zero sugar is starting to grow on me as I finally got my hands on it in Canada (with the new formula.)

Definitely prefer diet Pepsi over zero

People will argue both sides so it really depends on you. Some say the artificial sweeteners make you eat more or can result in feeling lethargic. If your calories are in check there’s no real harm.

Ding ding, correct.

Relevant pubmed studies:

• Sucralose affects glycemic and hormonal responses to an oral glucose load.

• Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels

Artificial sweeteners have very negligible calories. Aspartame, for example, has 4 Calories per gram (it is really a dipeptide of amino acids). But since it is almost 200 times sweeter than sugar, you need only super small amounts of it. A diet drink can have 5 or 10 Calories per serving and be allowed to say practically 0 calories. So you don't even have to worry about the literally few calories in your favorite diet drink, even drinking several a day.

Ruins your teeth even without the sugar (due to the acids used )