Can You Really Lose Weight by Pooping? It Depends on What You Eat

If you’re obsessed with either your scale or your bowel movements, you’ve probably wondered: How much of my weight is just poop? A teenage cousin of mine once spent an entire restaurant dinner arguing that he could lose up to 3 pounds if you just gave him a few minutes to sit on the toilet. As you might imagine, he was wrong. But not by that much, according to Thrillist, a site that’s been truly dominating the poop science beat lately.

You can indeed see the effects of a truly satisfying bowel movement reflected on your bathroom scale. (Wash your hands first, please.) But how much your feces weigh depends heavily on your diet. The more fiber you eat, the heavier your poop. Unfortunately, even the most impressive fecal achievement won't tip the scales much.

In 1992, researchers studying the effect of fiber intake on colon cancer risk wrote that the daily movements of poopers across the world could vary anywhere from 2.5 ounces to 1 pound. In their sample of 220 Brits, the median daily poop weighed around 3.7 ounces. A dietary intake of around 18 grams of dietary fiber a day typically resulted in a 5.3-ounce turd, which the researchers say is enough to lower the risk of bowel cancer.

A Western diet probably isn’t going to help you achieve your poop potential, mass-wise. According to one estimate, industrialized populations only eat about 15 grams of fiber per day thanks to processed foods. (Aside from ruining your bragging rights for biggest poop, this also wreaks havoc on your microbiome.) That's why those British poops observed in the study didn't even come close to 1 pound.

Poop isn’t the only thing passing through your digestive tract that has some volume to it. Surprisingly, your fabulous flatulence can be quantified, too, and it doesn’t even take a crazy-sensitive machine to do so. In a 1991 study, volunteers plied with baked beans were hooked up to plastic fart-capturing bags using rectal catheters. The researchers found that the average person farts around 24 ounces of gas a day. The average fart involved around 3 ounces of gas.

This doesn’t mean that either pooping or farting is a solid weight-loss strategy. If you’re hoping to slim down, losing a pound of poop won’t improve the way your jeans fit. Certainly your 24 ounces of gas won't. But to satisfy pure scientific curiosity, sure, break out that scale before and after you do your business. At least you'll be able to see if your fiber intake is up to snuff.