Diet soda has long been advertised as the healthier alternative to regular old fat soda. But as I learned previously while analyzing all the ingredients in Diet Coke, the artificial sweeteners in diet sodas (specifically aspartame) will still fuck you up pretty bad: “Even though Diet Coke might not have the calories that a regular Coke does, artificial sweeteners still affect our hormones like insulin in ways that can make us hungrier and reduce the amount of fat we burn,” physician and biochemist Cate Shanahan, author of Deep Nutrition: Why Your Genes Need Traditional Food, told me at the time.
As a result of the above, diet soda might even cause you to gain more weight than regular soda. One 2016 study showed that low-calorie sweetener users tend to have a higher average body mass index, a 2.6-centimeter larger waistline and a 53 percent higher incidence of abdominal obesity compared to participants who reported never using low-calorie sweeteners. Similarly, a 2008 study found that drinking artificially sweetened beverages was associated with an almost doubled risk of being overweight or obese.
For this reason, diet soda manufactures were sued last year for deceiving consumers into believing their beverages would help them lose or manage weight, when in reality, scientific studies have shown that they do the exact opposite.
All in all, diet soda is by no means a healthy choice—shocking, I know—even when compared to regular soda. But among the massive ranks of diet sodas, some are slightly less unhealthy than others. To find out which are least likely to scramble my insides, I asked Dana Hunnes, senior dietitian at the Ronald Reagan UCLA Medical Center, to help me rank some popular brands, from least unhealthy to most unhealthy.
Since most diet sodas contain more or less the same ingredients, Hunnes explains her methodology: “Basically, the clear diet sodas are the ‘safest,’ because they don’t contain artificial colors, which all seem to be potentially carcinogenic,” she says. “The dark diet sodas all contain caffeine, which isn’t good in high doses. Also, the caramel coloring is likely carcinogenic. Finally, the yellow diet sodas probably have the worst dyes in them.”
Hunnes also mentions that many of the diet sodas listed below contain acesulfame K (also known as acesulfame potassium), which is a calorie-free sugar substitute that may cause cognitive damage when consumed in high amounts over long periods of time.
In reality, the simplest way to rank diet sodas by how healthy they are is to simply lump them together by color, with clear diet sodas being the least unhealthy, dark diet sodas being the most unhealthy and yellow diet sodas sitting somewhere close to the dark ones. (Holy shit moment: This means Crystal Pepsi was the best Pepsi after all.)
But hey, if we can’t be needlessly pedantic in this column, where can we? Let’s get to the rankin’:
1. Diet 7Up and Sprite Zero (tied): Both contain aspartame and acesulfame K, but Hunnes says that these two light-colored sodas contain “the fewest number of questionable ingredients.” That’s because they don’t contain caffeine or artificial coloring.
3. Coke Zero and Diet Coke (tied): These both contain aspartame, acesulfame K and caramel color. “I’m not sure how Coke Zero differs from Diet Coke,” Hunnes says. “The ingredients list looks identical to me.” Shots fired, Coke Zero lovers!
5. Diet Pepsi: “This contains the artificial sweetener sucralose, which is possibly dangerous, and acesulfame K,” Hunnes says.
6. Diet Dr. Pepper: This contains aspartame and high amounts of caffeine.
7. Pibb Zero: This contains acesulfame K.
8. Diet Mug Root Beer: “This contains aspartame and quillaia extract, which is apparently used to treat athlete’s foot,” Hunnes says. Quillaia extract isn’t really anything to worry about, though: It’s frequently used as a foaming agent in root beers.
9. Diet Mountain Dew and Diet Sunkist (tied): “Diet Mountain Dew contains acesulfame K and yellow number 5 dye, which has been shown to possibly cause cancer,” Hunnes explains. “Food dyes terrify me—I don’t let my son eat them.” Diet Sunkist, meanwhile, contains contains aspartame and yellow number 6 dye, which is similarly carcinogenic.
It’s worth noting, however, that Shanahan previously told us that she has no real problem with artificial coloring: “I’ve always been of the opinion that studies claiming artificial colors can cause cancer are irrelevant because [in the studies] they use really high amounts of the artificial colors — like, a million times more than you’d ever get [in your] food [throughout your lifetime].”
Anyway, above all, the main takeaway here is that although clear diet sodas are better than dark ones, there’s no such thing as a healthy diet soda. “Your best bet is to drink carbonated water with fresh fruit juice,” Hunnes says. “I know, I’m such a bah humbug.”