Soda is the textbook example of a sugar-sweetened beverage, and its sugar content is startling when you translate the grams into teaspoons.
The numbers
A standard 12-ounce can of regular cola contains about 39 grams of added sugar — roughly 10 teaspoons, or nearly 10 sugar cubes. That's about 80% of the FDA's 50-gram daily value for added sugars in a single can. A 20-ounce bottle pushes past 60 grams, exceeding a full day's budget by itself. See what a gram of sugar looks like.
Why liquid sugar is different
Soda's sugar is almost entirely added, dissolved, and free of fiber or protein, so it floods the bloodstream quickly. And because liquid calories don't fill you up, a can of soda is usually consumed in addition to your regular food, not instead of it. This combination is why soda is so strongly linked to weight gain and metabolic problems.
The health links
Regularly drinking sugar-sweetened sodas is associated with higher risk of type 2 diabetes, obesity, tooth decay, and heart disease. The connection is strong enough that many cities have introduced soda taxes to discourage consumption. See sugar-sweetened beverages and health.
What about diet soda?
Diet sodas swap sugar for artificial sweeteners, cutting the sugar and calories to near zero. They avoid the sugar problem, though research on their long-term effects continues. Water, sparkling water, and unsweetened tea remain the simplest low-sugar swaps.