Coca Cola could be considered the earliest "energy drink" - although not marketed as such - it was one of the first carbonated drinks to contain caffeine.

The drink was first made in 1886 - where it supposedly had a very small level of cocaine in it - due to the extract of coca leaf being an ingredient. However, given that the formula has always remained secret - this may simply be an embellishment.

The Diet Coke range actually contains about 40% more caffeine per fluid ounce than the standard coke formula. Coca-cola Blak has the largest amount of caffeine of any coca-cola drink.