Caffeine is a drug. You can overdose on drugs. The Mayo Clinic says the safe daily limit of caffeine for healthy adults is 400 mg, which amounts to about five cups of coffee. Any more than that can cause migraines, an upset stomach, and muscle tremors. And according to caffeineinformer. com’s Death By Caffeine calculator, 155 shots of espresso in one day would kill the average 175-pound man.
Also relevant: in April, a South Carolina teen died of a “caffeine-induced cardiac event” after drinking a latte, a Mountain Dew, and a 16-ounce energy drink in a two-hour span.
So maybe keep that in mind when you order your next flat white.