In July 2013, famous Japanese fast eating competitor Takeru Kobayashi proved it was possible to drink a gallon of milk in one hour by accomplishing the task in 20 seconds. While the origins of the milk chugging challenge are not completely known, its popularity was given a boost by an episode of the U.S. television series "Jackass," where it showed Dave Engeland and Ehren McGhehey taking the challenge. The popularity of the gallon challenge as an odd form of entertainment stems from the inability of most people to consume such a large amount of milk without vomiting.
Although there are slight variations to the rules, the gallon challenge basically gives challengers one hour to consume a gallon of milk without vomiting. In some versions of the challenge, contestants who succeed in drinking a gallon of milk must also hold the milk in for a predetermined span of time. Rules on the type of milk that can be used also vary, in which the use of whole, skim or chocolate milk may or may not be used.
As impressive as the feat of Takeru Kobayashi was in milk chugging, it must be noted that he is a world-class fast eating competitor who trains in consuming large amounts of food in a short span of time. The video that shows him completing the challenge in 20 seconds also did not show if he was able or how for long he held it in.