Mountain Dew isn’t the single worst soda by every measure, but it does rank near the bottom on several health metrics that matter. It combines more sugar, more caffeine, and more tooth-damaging acid than most mainstream sodas, which is why it keeps earning its rough reputation. Whether it’s truly “the worst” depends on what you’re measuring.
How Mountain Dew Compares on Sugar
A 12-ounce can of Mountain Dew contains 46 grams of sugar. That’s more than Coca-Cola (39 grams), Pepsi (41 grams), and Dr Pepper (40 grams) in the same serving size. The difference might look small on paper, but Mountain Dew is rarely consumed in 12-ounce portions. A 20-ounce bottle, the standard size at gas stations and vending machines, packs about 77 grams of sugar, which is roughly 19 teaspoons.
The type of sugar matters too. Researchers at the University of Southern California’s Keck School of Medicine analyzed 34 popular beverages and found that sodas made with high fructose corn syrup, including Mountain Dew, Coca-Cola, and Pepsi, contain a fructose-to-glucose ratio closer to 60:40 rather than the 50:50 that manufacturers claim. That’s significant because fructose is processed almost entirely in the liver, where it gets converted to fat. A higher fructose load puts more metabolic stress on the liver than an equivalent amount of glucose, which the body uses directly as fuel.
Caffeine: Higher Than Most Sodas
Mountain Dew contains 54 milligrams of caffeine per 12-ounce can, according to the Center for Science in the Public Interest. That’s notably more than Coca-Cola (34 mg), Pepsi (35 to 38 mg), or Dr Pepper (41 mg). The zero-sugar version is even higher at 68 mg per can. None of these numbers are extreme compared to coffee, but among mainstream sodas, Mountain Dew consistently sits at or near the top of the caffeine chart. For people who drink multiple cans a day, that caffeine adds up quickly alongside the sugar.
The Dental Damage Problem
This is where Mountain Dew pulls away from the pack in the worst possible way. Mountain Dew has a pH of 3.14, making it highly acidic, but acidity alone doesn’t tell the full story. Research published in General Dentistry measured actual enamel loss by soaking tooth samples in various sodas for 14 days. Mountain Dew dissolved significantly more enamel than cola-based drinks. Across the board, non-cola beverages like Mountain Dew were two to five times more aggressive at destroying enamel than colas.
The reason isn’t just pH. The researchers found no strong correlation between a drink’s acidity level and the amount of enamel it dissolved. Instead, the overall composition of the beverage drives the damage. Mountain Dew’s combination of citric acid and other organic acids creates a particularly hostile environment for tooth enamel, more so than the phosphoric acid found in colas like Coke and Pepsi.
This effect has played out dramatically in parts of Appalachia, where heavy Mountain Dew consumption created a pattern of severe tooth decay that health professionals call “Mountain Dew mouth.” Dentists in the region describe seeing erosion from the acids and decay from the sugars working together, with some noting that the damage to teeth looks strikingly similar to what they see in methamphetamine users. The issue isn’t just drinking Mountain Dew occasionally. It’s the regional habit of sipping it constantly throughout the day, which bathes teeth in acid and sugar for hours at a time.
The Brominated Vegetable Oil Question
For years, Mountain Dew contained brominated vegetable oil (BVO), a food additive used to keep citrus flavoring evenly distributed in the liquid. BVO had been banned in several countries and linked to potential thyroid and neurological concerns in animal studies. The FDA revoked its authorization for BVO in food on July 3, 2024, with a compliance deadline of August 2025 for companies to reformulate. PepsiCo had already begun removing BVO from Mountain Dew before the ban, but the ingredient’s long presence in the drink contributed to its reputation as a particularly unhealthy choice.
What Actually Makes a Soda “The Worst”
If you’re ranking sodas purely by sugar content per serving, some regional and specialty brands contain far more sugar than Mountain Dew. Certain energy drinks and sweetened teas are worse too. But among the five or six sodas most Americans actually buy, Mountain Dew consistently ranks at or near the bottom across multiple categories: more sugar than the leading colas, more caffeine, significantly more enamel erosion, and a history of containing an additive that eventually got banned.
No single soda ingredient is harmless, and no mainstream soda is a healthy choice. But the combination of factors in Mountain Dew, especially the citric acid profile that makes it so much harder on teeth than colas, gives it a legitimate claim to the title. The drink isn’t uniquely dangerous in moderation. The problem is that its formulation creates compounding damage when consumed in the quantities many of its fans actually drink it, which tends to be more than a single can.
A 20-ounce bottle of Mountain Dew delivers nearly twice your recommended daily limit of added sugar, more caffeine than most sodas, and an acid bath for your teeth that’s measurably worse than what you’d get from a Coke. It may not be the absolute worst thing on the shelf, but among the sodas you’ll find in every convenience store in America, it’s a strong contender.