The average 20 year old is recommended up to 400 mg of caffeine a day.  That is about 4 cups of coffee, or 10 diet cokes or 2.5 Iced Lattes from Starbucks. Those figures can seem scary, especially considering how easy it can be to surpass them: a coke here, two teas there, and don't forget that Pumpkin Spiced Latte from the drive through! As a society, these products are so simple to get ahold of - but they should not be. Caffeine has many benefits, and are really helpful for keeping energy high, but it has some strong weaknesses too. Excessive caffeine can lead to anxiety, insomnia, digestive distress and elevated heart pressure.