How to Get Regular (Part 1 of 2)

An explanation of evidence-based strategies for improving regularity

Pooping – it’s something we all do but rarely talk about. A good bowel movement is just as much a fundamental aspect of health as getting a good night’s sleep, taking a walk, or eating a nourishing meal. Difficulty with regularity, which chronically impacts 12% of the population [1], creates significant costs for individuals and society. Consider this quote from a 2024 study by researchers Kang and Yan:

Constipation leads to anxiety, depression, and cognitive impairment, which seriously affect people’s quality of life. In addition, constipation increases the medical burden that the annual costs of constipation treatment are estimated to exceed $230 million in the United States. [2]

Despite the significant personal and economic costs of constipation, many individuals avoid talking about their bowel movements with their care providers due to societal stigma surrounding the topic [3]. Western culture pooh-poohs poo talk [4] to keep up the façade we are the one civilized species disparate from all the other animals who shamelessly defecate in their natural environments (how scandalous). We may be highly civilized (arguable), and we may be intelligent primates who choose to poop in tiny rooms with plumbing, but we’re just as much animals as those free-poop’n birds, bears, and bees (yes, bees poop).

Our society goes to great lengths to hide the existence of our animal nature, but avoidance of health topics leads to lack of education, and lack of education leads to poorer health outcomes. So let’s shrug off the scatological suppression and talk about healthy pooping! This 2-part article series provides explanations of evidence-based strategies for increasing and maintaining regularity. If you’d like to skip to the TL;DR version of this article, scroll down to the second-to-last section. You can also skip around to other sections if you’d prefer (they all have clear headings).

Disclaimer: The information in this article is evidence-based and provides general guidance for promoting regularity in healthy individuals, but it should not replace specific recommendations that may have been imparted to you by healthcare professionals (e.g. primary care provider or registered dietician).

The 90’s educational cartoon The Magic School Bus. A class of miniaturized elementary school students travel into their friend’s colon and almost get crushed to death by a fecal boulder à la the opening scene from Indiana Jones: Raiders of the Lost Ark. If a bunch of kids are brave enough to literally step foot in the colon, surely we adults can at least read about it.

Strategies that promote regularity

The lifestyle changes that encourage smooth, regular bowel movements are simple and easy to integrate, but they do require daily consistency to be effective.

Here is a list of the regularity-promoting strategies I’ll describe in this 2-part article series:

• Dietary fiber intake (part 1)

• Water intake (part 2)

• Physical activity (part 2)

• Supplementation (part 2)

Before describing the action-oriented strategies I’ve listed above, it’s important I provide a general explanation of the relationship between dietary fiber and large intestine anatomy & physiology. But again, feel free to skip around to other sections that may feel more relevant for you.

The importance of dietary fiber intake for regularity (and how pooping works)

This is the longest section of this article series because it establishes context for the following sections, which are comparatively much shorter and to the point. This section is also by far the grossest. But remember, pooping is a fundamental aspect of health; it’s the natural counterpart to eating. Food goes in one end of the tube, gets processed, and what remains exits the other end of the tube. Now let’s get into fiber and the large intestine.

From mouth to anus, the gastrointestinal tract is one long, continuous tube (~30’). Image source: NIH. Image use license: Noncommercial 2.0 Generic.

Dietary fiber is a form of plant carbohydrate the human body cannot digest and therefore cannot absorb calories from. Since dietary fiber is indigestible, it increases the bulk and softness of food waste (i.e. poop) passing through the large intestine (i.e. colon). Dietary fiber also attracts and absorbs water during its journey through the large intestine, which further increases the bulk and softness of poop as well as making it moister (I said this would be gross).

Increased bulk, softness, and moistness of poop directly increases the ability of the large intestine to keep the poop moving toward the rectum, which is the 2nd-to-last stop on the poop train, right before the final stop: la toilette. The large intestine contains layers of smooth muscle tissue that create involuntary, wave-like contractions (i.e. peristalsis) that keep poop moving toward the rectum. Once in the rectum, you decide the timing of the final stop of the poop train because the muscles of the external anus are under voluntary control (unlike the automatic muscle action of the large intestine). However, sometimes the poop train goes a bit off the rails and passes through the anus whether one likes it or not (it’s okay, we’ve all been there).

Here’s a 15-second video that shows the process of peristaltic contractions within the large intestine. That is, the contractions that cause wave-like movements that propel fecal matter along toward the rectum:

In order for the muscles of the large intestine to mechanically squeeze poop forward, the poop needs to be large, soft, and moist enough (again, fiber helps with all these factors).

• Largeness is important because the average diameter of the large intestine (at rest) is about 3 inches, and if the poop passing through the large intestine is, for example, a measly half-inch in diameter due to insufficient dietary fiber intake, the tubular muscles of the large intestine have to contract much harder so they can get narrow enough to make contact with the poop and mechanically squeeze it along toward the rectum.

• Softness is important for increasing the pliability of poop so it can easily deform and pass through the many sharp turns of the large intestine (see above video or image).

• Moistness is important so the outer surface of the poop can more easily slide along the inner mucosal surface of the large intestine.

The smaller, harder, and drier poops are, the more the large intestine needs to work to move them along, and the slower the process becomes (i.e. constipation). There is ample evidence to show sufficient dietary fiber can improve regularity [5,6,7,8], and this section has described the mechanisms by which that occurs. That is, increased fiber intake causes an increase in the size, softness, and moistness of poops, which helps poops travel more smoothly and quickly through the large intestine.

Raisin-like fecal matter makes for tough poop’n.

Dietary fiber intake recommendations

In the previous section I described why dietary fiber is important for regularity, and now I’ll explain fiber intake recommendations and ideal food sources for increasing one’s fiber intake.

Fiber facts and recommendations:

• On average, Americans consume less than half the recommended amount of daily fiber [6], so it’s safe to assume most folks can benefit from increased fiber intake.

• The recommended daily fiber intake for adults and children is 14 grams per every 1,000 calories consumed [6]. For example, if you eat 2,500 calories in a day, you should consume 35 grams of fiber (2.5 x 14 = 35).

• If you don’t know how many calories you eat in a day or aren’t sure how to estimate, here are more generalized fiber recommendations [9]:

  • Fiber intake for women: 25 grams per day

  • Fiber intake for men: 38 grams per day

• There are two kinds of dietary fiber: soluble and insoluble. Both types of fiber are important for promoting regular bowel movements [10]. As long as you eat varied fibrous foods, you don’t really need to focus on the specific intake of soluble vs. insoluble.

  • Soluble fiber absorbs water, dissolves, and turns into a gel-like substance in the colon.

  • Insoluble fiber attracts water into the colon while maintaining its solidity (think of those lovely bits of corn)

• Dietary fiber amounts can be found on food labels under “Nutrition Facts” (see image below).

• It’s advised to gradually increase fiber intake over time because a sudden, large increase can lead to gastrointestinal symptoms like excessive bloating and flatulence.

• More is not necessarily better. Regularly ingesting massive amounts of fiber (i.e. amounts well above recommended intake) can be counterproductive for gastrointestinal health.

Fiber content is easily findable on food labels.

Specific food recommendations for increasing fiber intake

These are the food groups that contain the highest amounts of fiber (in no particular order):

• Fruits

• Vegetables

• Whole grains

• Nuts

• Seeds

• Legumes

• Beans

Modern foods exist across a spectrum of wholeness to highly processed. To increase fiber intake, you’ll want to aim for the whole-er end of the spectrum because the more processed a food is, the lower its fiber content will be (in general). For example, a whole apple contains ~4 grams of fiber, but a cup of apple juice contains 0 grams. For general awareness, most animal products (like meat, cheese, fish, eggs, milk) have little to no fiber, regardless of how unprocessed they are.

Now I’ll list some particularly high-fiber options within the food groups mentioned above to give you some specific examples (this list is not exhaustive).

Fruits:

• Raspberries

• Blackberries

• Pomegranate seeds

• Blueberries

• Pears

Vegetables:

• Carrots

• Broccoli

• Brussels sprouts

• Kale

• Collard greens

Whole grains:

• Oats

• Barley

• Bran

• Corn

• Whole wheat products (e.g. pastas, breads, cereals)

Nuts:

• Almonds

• Hazelnuts

• Pistachios

• Pecans

Seeds:

• Pumpkin seeds

• Chia seeds

• Quinoa

Beans & legumes (all beans and legumes are quite high in fiber, but I’ll mention some specific options anyway):

• Peas

• Lentils

• Peanuts

• Kidney, pinto, garbanzo, soy, black, great northern, lima, and navy beans

A compilation of high-fiber foods.

TL;DR version

Small, hard, dry poops are more difficult for the large intestine to pass compared to large, soft, moist poops. Sufficient dietary fiber intake increases the size, softness, and moistness of poops, making them easier to pass.

The recommended daily fiber intake for adults and children is 14 grams per every 1,000 calories consumed per day [6]. For example, if you eat 2,500 calories per day, you should consume 35 grams of fiber per day.

If you don’t know how many calories you eat in a day or aren’t sure how to estimate, here are more generalized fiber recommendations [9]:

• Fiber intake for women: 25 grams per day

• Fiber intake for men: 38 grams per day

Here is a list of high-fiber food groups:

• Fruits

• Vegetables

• Whole grains

• Nuts

• Seeds

• Legumes

• Beans

What’s to come in part 2

Next week’s concluding article will explain the following strategies for promoting regularity:

• Water intake

• Physical activity

• Supplementation

See you then.

Anthropomorphized poop is fun for everyone.

---

References

1. Christodoulides, S., Dimidi, E., Fragkos, K. C., Farmer, A. D., Whelan, K., & Scott, S. M. (2016). Systematic review with meta‐analysis: effect of fibre supplementation on chronic idiopathic constipation in adults. Alimentary Pharmacology & Therapeutics, 44(2), 103-116.

2. Kang, Y., & Yan, J. (2024). Exploring the connection between caffeine intake and constipation: a cross-sectional study using national health and nutrition examination survey data. BMC Public Health, 24(1), 3.

3. Lin, J. N., Xie, W. T., Yang, Y. Y., Wu, C. H., & Wang, J. J. (2024). Living with constipation and communication taboos surrounding constipation among older adults: An interpretive phenomenology analysis study. Geriatric Nursing, 58, 266-273.

4. Szczygiel, M. E. (2019). Understanding Relatively High Social Visibility of Excrement in Japan. Silva Laponicarum, 60(61), 94-136.

5. Yang, J., Wang, H. P., Zhou, L., & Xu, C. F. (2012). Effect of dietary fiber on constipation: a meta analysis. World Journal of Gastroenterology: WJG, 18(48), 7378.

6. Anderson, J. W., Baird, P., Davis Jr, R. H., Ferreri, S., Knudtson, M., Koraym, A., ... & Williams, C. L. (2009). Health benefits of dietary fiber. Nutrition Reviews, 67(4), 188-205.

7. Schmier, J. K., Miller, P. E., Levine, J. A., Perez, V., Maki, K. C., Rains, T. M., ... & Alexander, D. D. (2014). Cost savings of reduced constipation rates attributed to increased dietary fiber intakes: a decision-analytic model. BMC Public Health, 14, 1-7.

8. Dukas, L., Willett, W. C., & Giovannucci, E. L. (2003). Association between physical activity, fiber intake, and other lifestyle variables and constipation in a study of women. Official Journal of the American College of Gastroenterology| ACG, 98(8), 1790-1796.

9. Slavin, J. L. (2005). Dietary fiber and body weight. Nutrition, 21(3), 411-418.

10. Foods for Constipation. [n.d.] John Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/foods-for-constipation