Does Poop Have Calories? (Everything you need to know)

Measuring poop calories is one of the standard methods in assessing the health of the microbiota and nutrient absorption. In this article I will explain the mechanism behind it and help you understand does poop have calories?

In general, poop does have calories because not all macronutrients are being absorbed in the digestion process. The number of calories in poop averages 4.91‚ÄČkcal per gram of stool. Several factors lead to fecal energy losses including fiber, fat, and duration of eating.

I also wanna show you some interesting studies that show the light on digestion, nutrient absorption and more.

Does Human Poop Have Calories?

Generally, human poop does have calories as all the macro and micronutrients aren’t sufficiently absorbed in the intestinal tract. The number of calories will depend on the microbiota health, nutrient absorption rate, and type of food consumed.

Do you poop out calories? In general, you do poop out calories because not all calories are being absorbed. This depends on the food composition and amount of fiber. High fiber foods trap the nutrients in the stool, which makes it harder to extract and absorb.

Here’s an interesting example of how this process works.

A doctorate-level research scientist Dr. Bridget Cassady examined how much energy from eating nuts is being lost in the stool. She also looked at the correlation between calories absorbed and the number of chewing performed during eating (Cassady, et al. 2006).

The group of 13 healthy adults consumed 5 g of almonds in three different chewing duration:

  • 10 chews
  • 25 chews
  • 40 chews

All participants had their stool collected and measured to assess fat and calorie content.

The results showed that people who chew their almonds 10 times had the most amount of calories in the stool (4900 KJ). People who chew almonds 40 times had more calories absorbed and significantly less in the stool (3100 KJ).

The amount of calories in poop after almonds experiment

Does poop contain fat? In general, poop does contain fat because some of the fat isn’t sufficiently digested and absorbed in the gastrointestinal tract. The amount of fat will depend on various factors like the fiber content of the food and incomplete mastication.

The researcher also looked a the fat content in the poop based on the number of chews. The results showed that people who chew their food longer had more fat absorbed, and people who only chew almonds for 10 times had more fat content left in the stool.

The amount of fat in the poop after almonds experiment

This experiment shows us that number of calories absorbed from the food is directly related to the number of chewing. With less chewing, your body will absorb fewer calories and will leave more in the stool.

This however has a secondary impact on satiety because more chewing stimulates satiety mechanisms better. So you may think that you will get fewer calories from chewing less, but in the long term, your satiety gets lower. Which means you get hungry sooner.

Do you poop out excess calories? Generally, you cannot poop out excess calories once they are all digested and absorbed. The only way to poop out calories is when your digestive tract cannot absorb nutrients efficiently so they stay in the stool and leaves the body with the bowel movement.

Learn more: Click here to learn more about “does paper have calories“.

Does Poop Have Nutritional Value?

Generally, poop does have nutritional values as some of the micro and macronutrients aren’t properly digested and absorbed. The number of micronutrients like sodium, calcium, or potassium in the poop varies depending on the moisture content.

A study done on 11 young Japanese female students showed that the moisture content of the poop range between 53 and 92%. The higher the moisture levels, the number of minerals goes up (Mamoru 2006).

Another fascinating study done on peanuts, peanut oil and peanut butter shows significant differences in the absorption of fat. Calories in poop were the greatest after eating whole peanuts, comparing to processed peanut oil or butter (Levine al at 1980)

As you can see in the graph, the type of food will indicate how much energy the body absorbs and how many calories are lost in poop.

The takeaway: Some foods are not fully digested and absorbed by the intestinal track which will increase the amount of calories in poop. More fat is absorbed from processed type of foods like peanut butter or peanut oil, comparing to whole peanuts.

Can You Lose Weight By Pooping?

As a whole, you can lose weight by pooping, however, this is only the waste weight, not the body fat. To lose weight the body needs to be in the calorie deficit, which starts to utilize stored body fat. Pooping reduces weight but only temporarily.

Why do I lose weight when I poop? Generally, you do lose weight when you poop because during defecation you lose several undigested particles of food, water, and gut bacteria. Foods that contain more soluble and insoluble fiber lead to greater stool volume and lower calorie absorption.

How much weight do you lose when you poop? On average, you lose around 50 – 150 grams of weight when you poop. The size and weight depend on the amount of water you drink throughout the day and the amount of fiber. A high fiber diet leads to greater defecation and increased transit time.

How many calories does pooping burn? In general, pooping, as a part of diet-induced thermogenesis (DIT) contributes to around 200 – 300 kcal (10% of total daily calorie expenditure). Things that contribute to DIT include fecal transit, bowel movement, together digestion, food absorption, and nutrient transportation.

Total daily energy expenditure consists of three main components: basal metabolic rate, diet-induced thermogenesis, and physical activity. The most metabolically expensive is the basal metabolic rate (70%) followed by physical activity (10-20%) and diet-induced thermogenesis (10%).

How Many Calories Do You Need To Eat To Poop?

Generally, pooping is not related to the number of calories eaten, but more to the amount of fiber. People who have a low fiber diet, on average have one bowel movement every 33 hours. People who have more fiber have one bowel movement every 19 hours.

One study done on pooping looked at the difference in stool frequency and composition, depending on the amount of dietary fiber in the diet. People who consumed more fiber had their stool weigh 151 grams (on average) and the frequency of one bowel movement every 19 hours.

On the other hand, people who ate less fiber had smaller stool volume (51 grams) and less frequent bowel movement (once every 33 hours (Beyer 1978).

Do You Poop More When You Lose Fat?

Generally, you don’t poop more when you lose fat because bowel movements are unrelated to fat loss. In fact, during a calorie deficit, it is normal to see less frequent bowel movements because of reduced total food volume and calorie intake.

I won’t be covering here the mechanisms behind calorie deficit and bowel movements. I’ve already done that in “do you poop less in a calorie deficit“, which I recommend you read.


Poop energy losses depend on a variety of factors like macronutrient composition, fiber and water amount, and also chewing. People who chew their food for longer may absorb more calories, however, this process initiates better satiety and fullness.

Michal Sieroslawski

Michal is an exercise physiologist (MSc), nutrition coach, Ashtanga teacher, and fitness blogger. He shares his successes and failures to help busy men and women squash down 20, 50, or even 100 pounds of fat without leaving their home.

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