A fast metabolism helps you lose weight! Speeding up your metabolism is a good thing! These are all sentiments you’ve likely heard in conversations about metabolism and weight loss. But this bodily process is about so much more than regulating your weight—it encompasses all the chemical processes that happen in your body as it converts food and drinks to energy. In fact, your metabolism also provides energy for things like breathing, circulating blood, and regulating body temperature. It even helps your body’s digestive system, per the Cleveland Clinic.
That’s right: Your metabolism and digestion have a connection. But does a fast metabolism make you poop more? While it’s not entirely important to know your metabolism speed (that is, unless, you have an underlying health condition that directly affects your metabolism, like diabetes), there are some signs your body gives that may offer insight.
“Metabolism can absolutely impact gut motility and pooping frequency, but it is just one of many factors in a very complex system,” says Wendi LeBrett, MD, gastroenterology fellow at UCLA Health in California. This means, it’s considered “normal” to poop anywhere from three times per day to three times per week, irregardless of your metabolism speed, says Dr. LeBrett.
Read on to learn more about poop frequency and metabolism, and whether your bathroom habits say anything about your metabolism speed.
How gut health and metabolism are related
Because metabolism and digestion are two separate systems within our body, it’s important to know how each one works on its own. According to the American College of Gastroenterology, digestion is measured by transit time and refers to how the body breaks down food and disposes of waste through the GI tract. Metabolism, on the other hand, is measured by calories used, and is the process of your cells using energy (from said digested food) for many bodily processes.
Theoretically speaking, if someone’s body works more quickly at processing and converting food to energy (i.e., a fast metabolism), their digestive system may also move faster, resulting in pooping more frequently. “A faster metabolism can lead to faster digestion and more rapid movement of food through the digestive tract,” says Jessie Wong, RD of the IBS Dietitian.
That said, there isn’t a ton of research to back this theory. More studies are needed to determine whether a fast metabolism directly causes an uptick in poop frequency. In other words, some people with a fast metabolism can still deal with constipation or slow gut transit time, while people with a slow metabolism can still deal with diarrhea or pooping more often. Plus, what’s considered a “normal” poop frequency is vastly different for everyone; it can be difficult to determine what’s due to metabolism and what’s not.
The bottom line? There’s a possibility that a faster metabolism could lead to faster digestion, but not everyone will poop more frequently because of this.
Other factors that affect pooping frequency
Metabolism speed isn’t the only factor that may affect how often you poop. According to Dr. LeBrett, poop frequency is not even the best measure of gut motility, or movement of food through the GI system.
A better measure of gut motility is actually the appearance of stool, which you can compare via the Bristol Stool Scale, Dr. LeBrett says. This scale categorizes stool texture on a scale of one to 10 to help determine how regular you are. “Type 1 and 2 stools correspond to constipation and slower gut motility, and Types 6 and 7 stools correspond to diarrhea and faster gut transit time, while Types 3 to 5 are within the range of normal,” Dr. LeBrett says.
Other factors that can affect gut motility include the following, per Dr. LeBrett:
- Dietary fiber intake: Eating too little (or sometimes too much) fiber can throw off your poop schedule.
- Hydration: Dehydration can lead to constipation, because your gut needs water to help move stool along.
- Stress: When you are stressed, you may find yourself running to the bathroom more frequently.
- Level of physical activity: Not getting enough daily movement has been linked to constipation and a slower gut.
- Gut microbiome health: If the delicate balance of bacteria in your gut gets thrown off (from infections, illness, stress, etc.), your bowels can become irregular.
- Hormone levels: Hormones are in flux all the time, especially in regards to your menstrual cycle. Shifting estrogen and progesterone levels have been known to contribute to things like diarrhea or constipation.
Speaking of microbiome health, an interesting study called the “Blue Poo study,” published in February 2021 in Gut, showed that diet and microbiome factors were more strongly associated with gut transit time than cardiometabolic factors. The study also showed having a shorter gut transit time was associated with better health and less belly fat (which is considered a marker of cardiometabolic health).
Other signs of a fast metabolism
Aside from a potential uptick in poop frequency, other signs of a fast metabolism may include the following:
- Higher body temperature: A June 2015 study in the Journal of Experimental Biology found that as body temperature rises, the rate of metabolism increases and then takes a sharp decline at super-high temperatures—a phenomenon called thermal performance curve.
- Increased hunger: Some people think that the hungrier you are, it must mean that you have a fast metabolism. The research surrounding this idea is mixed, though some medical professionals say that increased hunger and metabolism speed might be connected, per Harvard Health Publishing.
It’s possible for your metabolism to run too fast, too. This is usually a result of an underlying health condition like hyperthyroidism, for instance, which happens when your thyroid gland makes too much thyroid hormone, per the National Institute of Diabetes and Digestive and Kidney Diseases. Hyperthyroidism can also cause more frequent bowel movements (or even diarrhea) because the condition speeds up bodily processes like digestion, which can lead to shorter transit times and less water being reabsorbed from the stool, says Wong.
The metabolism and weight connection
What about weight loss? While some people think that the ability to lose weight easily means they have a fast metabolism, this is not necessarily the case. You can have a fast metabolism and still hold onto excess fat, or have a slow metabolism while losing weight. If anything, losing weight by going on restrictive diets may even slow your metabolism a little, per Ohio State University.
On the other hand, if you have frequent diarrhea, it can decrease your body’s absorption of nutrients because the food travels through the gut too quickly. “This could lead to weight loss despite eating sufficient calories, which could be misinterpreted as a fast metabolism,” Dr. LeBrett says.
The bottom line
It’s possible that people with faster metabolisms tend to poop more often. That’s because a speedier metabolism could contribute to digesting food quicker—i.e., food moves through the GI tract faster and causes more frequent bowel movements.
But metabolism speed is only a small piece of the poop-frequency puzzle. While a faster metabolism can slightly increase the frequency of bowel movements, your number of daily bowel movements is more strongly influenced by diet, fluid intake, and overall gut health. Remember, regardless of how speedy your metabolism really is, it’s perfectly normal to have bowel movements ranging from three times a day to three times a week.
Still, having a too-high metabolism is often a marker of an overactive thyroid, or hyperthyroidism. If you think your metabolism is too fast or too slow, consider visiting your doctor for a checkup and some blood work.
