Neither Pepsi nor Coke is meaningfully healthier than the other. A 12-ounce can of Pepsi contains about 150 calories and 41 grams of sugar, while the same serving of Coke has roughly 145 calories and 40.5 grams of sugar. That’s a difference of five calories and half a gram of sugar, which has zero practical impact on your health.
Still, the two drinks aren’t perfectly identical. Small differences in acidity, caffeine, and ingredients do exist, and they’re worth understanding if you’re choosing between the two or wondering whether either belongs in your regular routine.
Calories, Sugar, and Caffeine Side by Side
Both drinks deliver roughly the same sugar load per can. Pepsi edges slightly higher at 41 grams of sugar and 150 calories compared to Coke’s 39 to 40.5 grams and 145 calories. For context, 40 grams of sugar is about 10 teaspoons, which already exceeds the World Health Organization’s recommended daily limit of 25 grams (6 teaspoons) for added sugars. One can of either drink puts you well past that threshold.
Caffeine is similarly close. A 12-ounce Coke contains 34 milligrams of caffeine, while Pepsi ranges from 35 to 38 milligrams. You’d never notice the difference. Both are moderate compared to coffee, which typically delivers 95 milligrams or more per cup.
What’s Actually in Each Can
The ingredient lists overlap heavily: carbonated water, high-fructose corn syrup, caramel coloring, phosphoric acid, caffeine, and natural flavors. But there are two notable differences.
First, Pepsi lists both high-fructose corn syrup and sugar as sweeteners, while Coke uses only high-fructose corn syrup in its U.S. formula. This likely contributes to Pepsi’s reputation for tasting slightly sweeter. Second, Pepsi includes citric acid, which Coke does not. Citric acid adds a sharper, more acidic bite to the flavor and also affects how the drink interacts with your teeth.
The high-fructose corn syrup in both drinks is the HFCS-55 grade, meaning it’s 55% fructose and 42% glucose. Research published in the journal Metabolism found that HFCS-sweetened beverages produced higher blood levels of fructose, greater spikes in uric acid, and higher peak systolic blood pressure compared to drinks sweetened with regular table sugar. Since both Pepsi and Coke use HFCS as their primary sweetener, this concern applies equally to both.
Acidity and Your Teeth
All colas are highly acidic, but Pepsi is slightly more so. Regular Pepsi has been measured at a pH of 2.53, making it one of the most acidic mainstream sodas available. Coke is acidic too, typically falling around pH 2.6 to 2.7. For reference, pure water is pH 7 (neutral), and battery acid is around pH 1.
That extra citric acid in Pepsi’s formula is part of the reason. Both drinks contain phosphoric acid, but the addition of citric acid pushes Pepsi’s pH lower. Acidic beverages soften tooth enamel over time, and the effect is cumulative. If dental erosion is a concern, the practical advice is the same for both: drink water afterward, avoid swishing soda around your mouth, and don’t brush immediately after drinking (the softened enamel is more vulnerable to abrasion for about 30 minutes).
The Bone Health Question
You may have heard that the phosphoric acid in cola weakens bones. The evidence doesn’t support that in the way most people assume. A scientific conference whose conclusions were endorsed by the American Medical Association found that the effect of phosphoric acid in cola on calcium metabolism was “physiologically trivial.” For perspective, orange juice contains about twice the concentration of phosphoric acid that cola does (1.09% versus 0.55%).
The real issue is displacement. People who drink a lot of soda tend to drink less milk and other calcium-rich beverages. If your calcium intake is adequate, the phosphoric acid in either Pepsi or Coke isn’t going to erode your bones. If soda is replacing the foods and drinks that supply your calcium needs, that’s where the bone density problem starts.
What About Diet Versions?
Switching to Diet Pepsi or Diet Coke eliminates the sugar and calories, but it doesn’t automatically make the drink healthy. The WHO reviewed the available evidence on artificial sweeteners in 2023 and concluded that non-sugar sweeteners provide no long-term benefit for reducing body fat in adults or children. The review also flagged potential risks from long-term use, including a higher likelihood of type 2 diabetes, cardiovascular disease, and mortality in adults.
The WHO’s recommendation was straightforward: don’t use artificial sweeteners as a weight control strategy. These sweeteners have no nutritional value, and replacing sugar with them doesn’t appear to help with weight management over time. This applies to all common artificial sweeteners, including aspartame (used in Diet Coke and Diet Pepsi), sucralose, and stevia derivatives.
The Real Health Difference
Trying to pick the healthier option between Pepsi and Coke is like choosing between two nearly identical candy bars. The gap between them is so small that it disappears into the noise of your overall diet. A 5-calorie, half-gram-of-sugar difference per can is irrelevant to your health outcomes.
What does matter is how much of either one you drink. A 12-ounce can of Pepsi or Coke delivers 10 teaspoons of sugar in liquid form, which your body absorbs rapidly. Regular consumption of sugar-sweetened beverages is consistently linked to weight gain, type 2 diabetes, heart disease, and tooth decay. Those risks don’t change based on the brand name on the can. If you’re drinking soda occasionally, the choice between Pepsi and Coke is purely about taste preference. If you’re drinking it daily, the brand isn’t the variable worth worrying about.