When we set out to see if diet soda is somehow better for you thanregular soda, we quickly realized that the question was sort of like askingwhich brand of cigarette is best for distance runners, or whether death byimpaling is preferable to being crushed by a falling piano. There may be subtledifferences, but you go into the decision knowing both options are prettylousy. “I like to reject the question outright,” says Susie Swithers, aneurobiologist and professor of psychological sciences at Purdue. “Noone should drink a soda every day.”

Yes, if you down a daily diet soda (don’t feel bad, one infiveof us do), that might be better than regular, in much the same way that ifyou’re going to eat four pizzas, it’s best to stick with the Veggie Lover’s.Mathematically speaking, zero calories is less than the 140 found in regularsodas. “But if you look at the long-term outcomes of people who consume diet versusregular against people who don’t drink soda at all,” Swithers says, “sodadrinkers end up with way worse outcomes.” For instance!

• Thisstudyfound that people who drank diet soda every day had a 61 percent higher risk of "blood vessel diseases," such asstroke and heart attack, than those who drank none at all.

• And this one showed that olderpeople who drank diet soda over nine years picked up about triple the waist circumferenceand belly fat as their non-soda counterparts. (That’s the body circumferenceyou least want to increase.)

• Overweight or obese people who drink diet sodas eat significantly morecalories.

• Oh, and people who drink diet sodas are more aptto eat like crap.

• Diet soda tastes like aluminum foil. We have no science for that,but we stand by it.

In many ways, we’ve come to associate “diet soda” with “health” in thesame way we equate Lenny Kravitz with music—after a while, we just stoppedthinking about it critically and got used to it. And yet, through decades ofrelentless marketing, we’ve come to believe can-sized servings of sugar can beconsumed on the daily. “No adult would say, ‘It’s cool for me to have a bag ofSkittles every day,’ ” Swithers reminds us, “but with sodas you go, ‘I shouldhave that with my dinner.’ That’s effectively what soda is—candy in acan.”

There are three main problem groups here. First: Fake sweeteners likethe ones in some diet sodas are up to hundreds of times sweeter than sugar,which gets your system used to synthetically sweet foods. Second: Our bodiesare trained to associate “sweet” with “calories.” When you start untying thatconnection, it throws the system out of whack and might actually increase thecraving for real sugar, since you technically haven’t gotten your fix yet. Third:It now seems possible, just possible, that drinking a stew of chemicals—includingphosphoric acid (which leeches calcium from the bones), aspartame (which weconvert into formaldehyde), sodium benzoate (that’s bad), and two coloringcompounds that start with “methyl-”—is not altogether awesome for you.

So while diet soda may, in some twisted sense, be "better" for you thanregular sugar-sweetened soda, Swithers reframes the question: “Why do you thinksoda is a good idea?”