Do You Poop Less In A Calorie Deficit?

One of the most common thing I’ve noticed when doing calorie deficit was change in my bowel movements. In this article I will explain everything you need to know about pooping and dieting.

Do you poop less in a calorie deficit?

You do poop less in a calorie deficit because calorie and food restrictions often lead to decreased gastrointestinal motility. Calorie deficit, especially on a very low-carbohydrate diet, can lead to infrequent stools, difficult stool passage, or both.

Plus, there are other multiple factors, that work synergistically to affect your gut permeability (how easily the poop passes through) while dieting.

Do You Poop Less When You Eat Fewer Calories?

Eating fewer calories leads to having less food pass through your gut. This means peristaltic movements can slow down, which leads to less frequent pooping.

Do you poop less when you eat fewer calories?

You do poop less when you eat fewer calories because the amount of food you have to pass transit through the intestinal tract, and with less food, the gut motility decreases. Those changes are mainly due to acute caloric restriction, rather than a decrease in body weight.

Some people may think that with weight loss you poo less, but it’s not the case.

One study done on twenty women who underwent calorie deficit for 4 weeks:

  • Before dieting around 1700 calories per day
  • During the study 800 calories per day

After 4 weeks later, the results showed that on average each person:

  • Lost a significant amount of weight (on average 7kg)
  • Lower their BMI (on average -2.5)
  • Lower body fat (on average -4.2)
  • Lower waist circumference (on average -5.7cm)
  • Lower hip circumference (on average -4.5cm)

However, at the same time, every person reported lower gut permeability and frequency in bowel movements.

After 4 weeks, every woman was asked to participate in 2 weeks of follow-up with a regular diet.

After 2 weeks of follow up, gut permeability and stool frequency increased significantly again.

This study shows that less pooping, during the calorie deficit, is done because of the amount of food consumed, not because of the weight loss.

Because after 2 follow up the week, non of the women gain the weight back, but they all increased their poop frequency (source).

Why Do I Poop Less On A Diet?

There are several explanations why people lower their peristaltic motility during weight loss. Apart from food amount, things like water content, fiber, medication, and stress also play a role.

Why do I poop less on a diet?

The reason why you poop less on a diet is because of the lower food intake that is required to stimulate bowel movements. But it can also be low carbohydrate intake that influences water levels, not enough amount of fiber in the diet, or a high amount of stress.

Eating Healthy But Not Pooping

Eating healthy but not pooping can be the effect of the low-calorie diet, where you just eat less food. But it also can be because of changes or lack of physical activity, low water absorption, use of laxatives, and absence of fiber in the diet.

The gut permeability is strongly related to:

  • The amount of food you eat

The amount of food will be the most important predictor of how much you will poop. Peristaltic movements are triggered when you eat, and with less food coming in it will lower the frequency of poop.

So lowering your calories also comes hand in hand with lowering the food bulk that enters the body.

  • Food type

It is been shown that a low amount of fiber in the diet can affect bowel movement. A diet that has a low amount of fiber can lead to constipation, bloating, and difficulty in relaxing. Enough fiber in the diet adds bulk to the stool where it can freely transit through the intestinal tract.

One study compare group of healthy man eating low-fiber diet with high-fiber diet.

Low fiberHigh fiber
Stool weight51g157g
Number of bowel movementsOnce in 33hOnce in 19h
Transit time48h19h

Looking at the chart above you can see how lack of fiber can affect bowel movement.

So even when you’re on the calorie deficit, making sure that you consume high-fiber foods will help you be more regular, despite weight loss.

Extra fiber can also help you with a calorie deficit because it gives you better satiety.

  • Water intake

The very low carbohydrate diets are effective to reduce the amount of glucose and lower the insulin response which can lead to weight loss. However, with a low amount of carbs, we also lose water levels.

And to form the stool, apart from fiber you also need water.

For every gram of carbohydrates out body stores 3 grams of water. And when you eliminate carbs from your diet, your body doesn’t retain water as it used to. That’s why people lose a lot of weight in the first week, because it’s all water weight.

But this water loss also leads to less pooping. So even when you think yu drink the same amount of water like before dieting, this may be not enough to be regular.

Drinking more water daily can help you solve the problem.

  • Physical activity

Regular aerobic and resistance training exercise has numerous benefits on our physiology.

One of the most noticeable effects has on intensities and gut permeability. In other words, exercise improves markers of gut integrity.

This also works in both ways.

If you’ve been physically active, and for some reason, your lifestyle changed, because of the lower physical activity you can notice a decline in bowel movements (source).

Related article: Does poop have calories

Can Changing Diet Affect Bowel Movements?

A lot of things affect how we poop. This can be as simple as a new diet, food frequency but also psychological aspects like traveling, sleeping in a new place, using a different bathroom, or even stress can all alternate our bowel movement pattern.

Can changing diet affect bowel movements?

Changing diet can affect bowel movements because new types of foods, food composition, and even the new eating environment play a significant role in how often you have your bowel movements. Having enough fiber and drinking enough water can help be more regular.

So apart from the diet there are several things that affect our gut.

And if you’ve ever had an upset stomach while thinking about something. Or had to quickly run to the bathroom after an emotional event.

Then you know that gut is an interconnected system that works synergistically with the rest of the body. And it can be triggered by emotions, social interactions, feelings, thoughts, and memories (source).

This is the part of the enteric nerous system and nothing we can do about. So it’s out of your control.

But things that are in your control is drinking more water and eating more fiber-rich foods.


Calorie restriction, changing the environment, changing diet, and stress can all alter the frequency of your bowel movement.

The best practice you can do is to make sure you’re drinking enough water, eating fiber rich foods, stay physically active, get plenty of rest and be mindful when traveling.

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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