The whole thing with a gallon-of-milk-in-an-hour challenge apparently became interesting to people, and then became an official high school and college challenge, because of an episode of Jackass. And apparently there are not many people who can complete the challenge without puking their guts out. But why? What makes milk so difficult to drink?
Let's begin by noting that drinking a gallon of anything in an hour can be hazardous. Even a gallon of water can, potentially, be fatal if you drink it quickly:
The summary of the above article: Too much water overloads the circulatory system and the kidneys, dilutes blood electrolytes and can cause cells to swell, potentially causing brain damage or death.
Drinking a gallon of soda in an hour would also be very bad. A gallon of soda contains over 100 teaspoons (400 grams) of sugar and way too much caffeine (450 mg) for your body to safely process.
So it is not surprising that a gallon of milk is also problematic. The three things in milk that are vomit-inducing include: 1) The lactose (also known as milk sugar) 2) The calcium 3) The casein
The problem with lactose is that your body can only process so much of it at a time. You need the enzyme lactase to deal with lactose. People who are lactose intolerant can't process any lactose, and they may throw up from just one glass of milk. In drinking a full gallon of milk, most people burn through their available lactase and then become lactose intolerant during the challenge. (You might be able to take supplemental lactase to solve this problem, but then you get the same kind of blood sugar spike you get from drinking soda, and that may cause you to puke anyway)
The problem with calcium is that milk contains a lot of it - about 300 mg per 8-ounce glass. A Tums chewable tablet contains about 200 mg of available calcium. So in drinking a gallon of milk, it is like downing 25 Tums tablets at once. That is a big handful of Tums. It messes up the acid balance in the stomach, giving your stomach another reason to consider puking.
The problem with casein is that it also wants to react with the acid in your stomach and instantly turn to cheese, as shown here:
So your stomach fills with stringy curds, which is yet another reason to puke.
You add all three together and, chances are, you are going to puke your guts out after drinking a gallon of milk. But some people are able to survive for at least an hour before puking, as demonstrated here:
Even so, he ended up puking shortly after winning the bet. Unless you enjoy puking, the gallon-of-milk challenge is one challenge that it might be best to avoid.
See also: - What is the big deal about milk? Why do people treat it like some kind of miracle drink? - If you insist on watching someone try the gallon-of-milk challenge, here is a profanity-free way to witness the result: Gallon of Milk Challenge - 9/4/08
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