It is not simply a measurement of what goes in and out of the body. The weight loss associated with having a bowel movement is temporary. This is because the body is constantly processing food. Also, people will gradually replace the waste matter that leaves the body as stool by eating more food.
You can lose weight from pooping, but it's very, very slight. “Most stool weighs about 100 grams or 0.25 pounds. This can vary based on a person's size and bathroom frequency. That said, poop is made up of about 75% water, so going to the bathroom gives off a little bit of water weight,” says Natalie Rizzo, MS, RD.
When you have a bowel movement, you're emptying your colon. Depending how much you go, that visit to the ladies' room can add up to half a pound a day—hence the reason you feel so much lighter after you poop.
Your weight fluctuates throughout the day depending on your level of activity and what you eat. So while you probably already know that it's best to weigh yourself first thing in the morning — before you've eaten or used the bathroom — you should also add one more parameter to the list: before showering.
The Best Time to Weigh In
You should step on the scale first thing in the morning. That's when you'll get your most accurate weight because your body has had the overnight hours to digest and process whatever you ate and drank the day before. And you should try to turn that step into a regular part of your routine.
Research on fecal weights has found that a person's poop can weigh as little as 72 grams (about 2.5 ounces), or as much as 470 grams (about 16 ounces or 4 pounds).
Pooping doesn't help you lose weight, apart from a drop in the scale you might notice after a large bowel movement. Although you may feel lighter and less bloated after having a bowel movement, it's not because you've lost body weight. Weight loss happens when you burn more calories than you consume.
You're Constipated
Being "backed up" can cause you to weigh more until your body releases the waste it's hanging onto. It's not uncommon for women to experience constipation as part of PMS (lucky us!), but stress, too little sleep, and travel can also be triggers.
A person may lose a very small amount of weight when they have a bowel movement. How much weight this is differs for every individual, but in general, it is not significant. As the body passes stool, it also releases gas. This can reduce bloating and make a person feel as though they have lost a little weight.
The truth is, this strategy can backfire. People think that by skipping food intake, they'll lose weight. But what you really need to be concerned about overall is total daily calorie intake. The problem is that when we go without food, fat-storing enzymes increase and metabolism decreases as a means of preservation.
A person should avoid weighing themselves at gyms, health clubs, and other fitness facilities. Although the scales may be accurate, there are more variables that are hard to control, such as the time of the day, activity level, and clothing choices.
You're constipated. Having a bowel movement at least every other day is considered normal. Strict diets, skipping meals and restricting fluids can lead to constipation which can add 2 to 6 pounds to the scale. Ease constipation by increasing fiber-rich foods, water and exercise.
In short, yes and no. Constipation and weight gain are linked, as factors contributing to constipation, bloating and fullness can cause weight gain, but constipation itself is only likely to cause an increase in weight in the short term (a matter of a few hundred grams per day) until your constipation eases.
The intestines can hold as little as 5 pounds and as much as 25 pounds of waste at any given time, varying greatly depending on your weight and diet. This is because your body is physically unable to completely digest all the foods you consume and some of them can get stuck in the lining of your intestines.
As your body metabolizes fat, fatty acid molecules are released into the bloodstream and travel to the heart, lungs, and muscles, which break them apart and use the energy stored in their chemical bonds. The pounds you shed are essentially the byproducts of that process.
On average, you sweat about 25ml per hour of sleep under temperate conditions (around 85 degrees Fahrenheit). ² If you sleep for an average of eight hours, that's around 200ml of sweat per night. This would equate to a drop in weight of approximately 200g overnight.
Clothing. Wearing clothing while weighing yourself can add up to two pounds—more if you're wearing shoes. Again, this isn't a big deal if you consistently weigh yourself wearing the same thing, but since our clothes vary with our moods and seasons, it's best to go without when you step on the scale.
One is fat, the other is muscle. The fat dumbbell would weigh 1kg the muscle dumbbell would weigh 3kg. But they would obviously both take up exactly the same amount of space. This is why your clothes could feel a lot looser even when the scales haven't changed that much.
Muscle is denser than fat, and as it is more compact within your body, as you gain muscle mass, you end up looking thinner, no matter your physical weight. So, if you've been doing a lot of strength training lately, it's likely this is the reason that you're looking fantastic but not dropping those numbers.