Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, it's Christian Seger. Have you ever heard of this gallon of milk challenge before? Here's the idea. You try to drink a gallon of milk and hold it down for an hour without puking. That sounds unnecessary to me, but I mean it's called the challenge, and you don't win anything, I think, but still, thousands of people have tried it and failed. So if you've already heard of this, then
you've probably heard it's impossible. But spoiler alert, it's not. It's just really hard and really gross. So what makes drinking milk difficult? Well, let's begin with the basics. Drinking a gallon of anything in an hour can be hazardous. Even a gallon of water can be fatal if you drink it too quickly. Too much water overloads the circulatory system and the kidneys, elutes blood electrolytes, and can cause
cells to swell, potentially causing brain damage or death. So it's not surprising that a gallon of milk is also bad business stomach wise, most people who attempt it vomit. There are a few proposed causes for this condition. You'll often hear people blame lactose for the pucatude let's call it of milk. Lactose is essentially milk sugar, and your body can only process so much of it at a time.
You need the enzyme called lactasee to deal with lactose, and the idea here is that people who are lactose intolerant can't process any lactose and they may throw up from just one glass of milk. But nutritionists like Dr Sarah Ash at North Carolina State University point out that lactose intolerance is a problem of the large intestine, not
the stomach. Since pctose is digested and absorbed in the small intestine, the trouble doesn't really hit until it passes to the large intestine, where it's consumed by bacteria, producing diarrhea and gas fun both unpleasant in their own ways, but nothing that could stop you from holding the milk down. Then there's calcium. Milk contains a lot of calcium, about
three hundred milligrams per eight ounce glass. A Tom's chewable tablet contains about two hundred milligrams of available calcium, so drinking a gallon of milk is like downing twenty five Tom's tablets, it messes up the acid balance in the stomach, giving your stomach another reason to consider puking. The most likely culprit, however, is surprisingly simple. It's just stomach size, guys. The average stomach can hold about a half a gallon
of well whatever. More than that, you run the risk of triggering these stretch receptors in your stomach, which can induce vomiting. There are a few people with the ability to complete this challenge, like professional competitive eaters, but for most of us, this is a pipe dream that could quickly turn messy. So while chugging a gallon of milk may be more difficult than chugging water, it turns out that drinking a gallon of anything this quickly just isn't
a great idea. Check out the brainstuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com.