Why Do You Throw Up when Drinking a Gallon of Milk?

The Challenge

The milk challenge (also called the gallon challenge) is a beverage endurance test popularized by the fine folks of MTV's "Jackass." Though the segment is not currently available on any "Jackass" DVDs (for licensing reasons due to the use of a song), it contains professional Jackasses Dave England and Ehren McGhery trying to drink 1 gallon of milk in less than 1 hour. This attempt was filmed in Portland, Oregon, in 2000 and concluded in failure as no contestants were able to complete the gallon challenge without vomiting. (see References 1) The milk challenge has since spread in popularity in colleges and high schools, despite its difficulty and less-than-appetizing results. While it is not impossible for a human being to consume 1 gallon of cow's milk in less than 1 hour without vomiting, it is, at best, not advisable.

The Science

The milk challenge is indeed a challenge for several nutritional reasons. Cow's milk contains a substance called lactose (or milk sugar) that most human beings can digest without nausea, discomfort or vomiting. This is due to an enzyme produced in the human small intestine called lactase. Humans who are lactase deficient (also called lactose intolerant) are not able to fully digest this enzyme and will experience digestive problems that can include vomiting. (see References 2) Drinking 1 gallon of milk in less than 1 hour can overwhelm an otherwise healthy digestive system's capacity to digest lactose, and also compounds the problem by introducing large quantities of fat and protein. The basicity of milk can also cause the stomach's normally low pH levels to rise suddenly, which is another factor that can induce vomiting. (see References 3)

The Results

Though the popularity of the milk challenge has increased, and while it is not necessarily dangerous, it is not recommended. Hopefully, this article has sated anyone curious enough to attempt the challenge. If you are still chomping at the bit to attempt it, there is an annual, official Gallon Challenge that is now a charity event. Participants are charged a small fee, and each year's winners (those who do not vomit and complete the challenge with the best times) are awarded prize money. If the idea of vomiting up 1 gallon of milk has still not dissuaded you, then perhaps your steadfast determination can contribute to a charitable cause. If you are reading this article, you probably have a strong stomach and an adventurous sense of curiosity, but it should be mentioned that some of the references at the bottom of the page contain pictures of individuals in the process of losing the milk challenge. Please click with caution.