Fiber to the Rescue

One of my favorite things about being a clinical dietitian is the opportunity to be connected to an awesome network of colleagues. The RDs I’ve been privileged to work with are a major resource for me when it comes to the day-to-day care of my patients. In the early afternoon, after we’ve seen most of our patients, we’ll gather in the office and discuss some of the more complex or interesting cases, probing each other for insight and hoping to reach an educated, science-based consensus to support a particular nutrition intervention.

Then, of course, there are the days we just talk about poop.  That’s right, we talk about poo all the time. How often it’s happening, its consistency, its behavior in the toilet… (you should know that a lot of these conversations happen over lunch breaks. It doesn’t phase us). A patient’s poop status is an excellent gauge for evaluating the efficacy of our nutrition intervention. A patient with constipation is told to eat more fiber, drink more water, and get up and get moving (even if it’s walking up and down the halls). We check back in a few days to see if the situation has… resolved.

Unfortunately, a hospital stay isn’t the only time us Americans have issues with pooping.  Take constipation. There are over 25 million doctor visits attributed to constipation a year, and we spend hundreds of millions on laxatives each year. Some folks will sway between episodes of constipation and diarrhea, accompanied by gas and bloating.  A lot of these people (an estimated 10-15% if the US population) are diagnosed with Irritable Bowel Syndrome (IBS). IBS is a disorder of gastrointestinal function characterized by alternating bouts of constipation and diarrhea, gas, bloating, and abdominal pain.


(what’s your poop look like? Optimal is Type 4 or 5.)

We can all probably relate to the occasional (or not so occasional) bout of constipation or diarrhea and the desire for a quick fix like a laxative or Immodium. You know you’ve been there, so don’t deny it. But when I speak to my patients about their gastrointestinal woes (and trust me, almost all of them have something going on), I talk about diet. Following a healthy, balanced diet with adequate fiber on the regular will keep you from running to the store for meds.

You’ve probably heard of fiber, know you need to get a certain amount of it every day, and understand it has a role in promoting bowel regularity. But there’s oh-so-much more to fiber than most people realize.

Fiber is the name given to a class of indigestible carbohydrates. Some examples of fibers include cellulose, lignans, pectin, inulin, beta glucan, and resistant starch. Fiber is found naturally in plant foods. It’s also added to foods by manufacturers (think FiberOne bars). Animal products (meat, cheese, dairy) have no fiber.

There are two types of fiber: soluble and insoluble. Both are awesome, but they do different things.  Eating enough of BOTH will optimize their benefits.

Soluble fiber is, obviously, soluble in water. This means it expands and gels in a liquid environment (like your gut). Soluble fiber SLOWS the movement of stool by creating bulk. This is cool if you are experiencing diarrhea. Soluble fiber has also been shown to help reduce cholesterol levels and mitigate the rise in blood sugar after a meal (especially good for diabetics). Find soluble fiber in bananas, apples, oatmeal (not instant!), nuts, and legumes (black beans, kidney beans, lentils, etc). In the hospital, patients with diarrhea are often given a fiber supplement (pectin, Metamucil, or banana flakes). In fact, most over the counter fiber supplements you can get at the store are soluble fiber.

Insoluble fiber is not soluble in water, and therefore moves quickly through your digestive tract, taking with it your stool. Awesome if you’re constipated. I see chronic constipation very often in people who eat a diet high in animal products (especially fast food) and low in fruits and veggies. Insoluble fiber is found in almost all fruits and veggies, as well as whole grains.  Unfortunately, over the counter fiber supplements won’t be much help with constipation – loading your system with MORE soluble fiber and NO insoluble fiber will only make the problem worse.

A lot of observational studies (where researchers follow a group of people over a period of time, record their diet and record their risk of developing certain disease) have linked a high fiber diet with decreased risks of disease like heart disease, diabetes, metabolic syndrome, and some cancers. Now, correlation does not equal causation, and these high-fiber fanatics were probably just healthier people overall. But it still seems like a diet rich in both soluble and insoluble fibers is a no-brainer. Fiber has also been touted as an aid to weight loss because it makes you feel fuller for longer (think about soluble fiber gelatinizing in your gut…mmmm) and leads to less overeating. One recent study even found a high fiber/high fruit diet was associated with decreased risk of all-cause death. Whoa.

The easiest way to make sure your meals are fiberful (yes, I just made that up) are to make half the food you eat fruits and vegetables.  Whether you’re eating off of a plate, from a bowl, or directly from the fridge (I don’t condone this but, sure, I’ve been there), fruits and veggies need to be center stage.

Next, stop buying white bread! Seriously, there is nothing healthful about white bread. It’s a source of calories, yes, but not much else. Make sandwiches, French toast, stuffing, and toast with whole grain versions of bread products (bread, bagels, English muffins, tortillas, flatbreads, pasta, pitas – you name it, they make it).

I get so excited when my patients tell me they eat oatmeal everyday, until they tell me it’s instant strawberries and cream or maple and brown sugar. Gah! This stuff is like junk cereal – packed with sugar and stripped of almost all the whole-grainy goodness that old-fashioned, unprocessed oats provide – including the fiber. Old-fashioned oats are super cheap and super easy to prepare. Add your own fruit and a little milk. You can even cook in an egg for an extra powerful energizing breakfast (click here for more deets).

Legumes – like beans and lentils – are great sources of soluble fiber (and plant-based protein). They do give some people gas, so I wouldn’t advice eating a huge bowl of curried lentils (really good recipe here) before your big date.  But try incorporating them into your menu planning and pairing them with insoluble fiber-rich veggies or whole grains.

This is important: whenever you are increasing the fiber in your diet, you MUST increase your fluid intake.  Water is important in making sure BOTH types of fiber work the right way – to aid in the bulking process and to move things through at a regular pace.  Eating lots of fiber and skimping on water can lead to symptoms getting worse. Drink 64 ounces a day.

A word on exercise and physical activity. While anecdotally, increasing exercise seems to work for people (and I always recommend it to patients in the hospital), its benefit in constipation is not super well-documented in the literature. Take that as you will.

The key to making this all work for you in the long term is consistency. The goal is bowel regularity. This means different things to different people, but basically, you want to feel comfortable most of the time. That might mean going once a day, or it might mean 3-4 times a week.  While you might not see a change in your symptoms immediately, I can almost guarantee that you’ll see some improvement after a few weeks or months of following a healthier diet with lots of fiber (if you don’t, and your symptoms are severe, please go see your doctor). You’re trying to get 25 – 30 grams a day. You can go over that, but go slowly and stay hydrated.

People that know me well know that I could talk about healthy pooping all day long. I will spare you for now, though, and pick up in a future post with probiotics and prebiotics (the latter of which are typically fibers) and their role in promoting healthy gut bacteria. This is a fascinating area of study we are still learning about, with implications for a whole host of health concerns. Until then, eat a piece of fruit, for cryin out loud.

And happy pooping.


(if you want to buy me a present…. this mug is available from Amazon)

Links: (image source for Bristol Stool Scale)


Pereira MA, O’Reilly E, Augustsson K, et al. Dietary fiber and risk of coronary heart disease: a pooled analysis of cohort studies. Arch Intern Med. 2004;164:370-6.

Rimm EB, Ascherio A, Giovannucci E, Spiegelman D, Stampfer MJ, Willett WC. Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men. JAMA. 1996;275:447-51.

Brown L, Rosner B, Willett WW, Sacks FM. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Am J Clin Nutr. 1999;69:30-42.

Whitehead, A, et al. Cholesterol-lowering effects of oat B-glucan: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2014: 100:1413–21

McKeown NM, Meigs JB, Liu S, Wilson PW, Jacques PF. Whole-grain intake is favorably associated with metabolic risk factors for type 2 diabetes and cardiovascular disease in the Framingham Offspring Study. Am J Clin Nutr. 2002;76:390-8.

McKeown NM, Meigs JB, Liu S, Saltzman E, Wilson PW, Jacques PF. Carbohydrate nutrition, insulin resistance, and the prevalence of the metabolic syndrome in the Framingham Offspring Cohort. Diabetes Care. 2004;27:538-46.

Fung TT, Hu FB, Pereira MA, et al. Whole-grain intake and the risk of type 2 diabetes: a prospective study in men. Am J Clin Nutr. 2002;76:535-40.

Buil-Cosiales, P., et al. Fiber intake and all-cause mortality in the Prevencion con Dieta Mediterranea (PREDMED) study. Am J Clin Nutr. 2014; 100:1498–507


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