A 12-ounce can of soda delivers about 10 teaspoons of sugar — more than the American Heart Association’s daily recommendation of 6 tsp. per day for women, 9 tsp. for men. Normally you’d gag on such intense sweetness, but phosphoric acid mellows the sugary flavor.
Here comes the blood-sugar spike. Your liver reacts quickly to the glucose in your bloodstream, storing as much as it can, but it’s soon at capacity and most of the sugar is converted into fat. (And there’s practically no limit to how much fat your body can store.)
Caffeine’s effects are under way: Your pupils dilate. Heart and respiratory rates increase. Your blood pressure rises, causing your liver to release even more sugar into the bloodstream. If you’re tired, you won’t feel it: Caffeine blocks the brain’s adenosine receptors.
Dopamine levels rise abnormally, turning on the pleasure centers in your brain and creating a revved-up “high” similar to the one produced by amphetamines, cocaine, and heroin.
The diuretic properties of caffeine make you pee. And because the phosphoric acid in soda binds to calcium, magnesium, and zinc in your body, you’ll soon be flushing those vital nutrients down the toilet.
A sugar crash hits you — hard. You’re left feeling cranky, sluggish, thirsty, and ready for another soda, especially if it’s diet. The artificial sweeteners used in diet soft drinks also affect the addiction centers in the brain, keeping you coming back for more.