You Are What You Poo
What Your Body's Solid Waste Can Tell You about Your Diet

April 30, 2008

By Charles Stuart Platkin

I'm going to warn you right now: If you have an aversion to your body's waste, don't read any further. However, if you're like most people, you're probably very interested in what your stool can tell you about your diet and your health. Who better to answer our questions and tell us a bit about our poo then Anish Sheth, MD, a gastroenterology fellow at the Yale School of Medicine and the co-author of the best-selling book What's Your Poo Telling You? (Chronicle Books, 2007).

Diet Detective: Do we put out exactly what we take in? Are the qualities and types of food the only things that affect what comes out? Or are there multiple forces at work, such as genetics, overall health, etc.?

Dr. Sheth: Sure, there are many factors that determine what our stool looks like. The main modifiable component is our diet, with fiber being responsible for the girth, weight and consistency of our stool. Other factors include transit time (how long it takes the stuff we eat to move through our system), medications (which can cause both constipation and diarrhea and even change the color of our stool bismuth turns it black), and underlying diseases that may affect our ability to digest food properly (i.e., celiac disease).

Diet Detective: Should people be paying more attention to what comes out of them for health reasons? Or do most of us already pay more attention than we let on?

Dr. Sheth: Yes and yes. On a day-to-day level, taking a quick glance can let us know about our diet (whether we are eating enough fiber, etc.). It can also give clues to the multitude of ailments that affect our GI tract (bleeding could mean inflammatory bowel disease or cancer; fatty stools could indicate liver or pancreatic disease, etc.). I think most people do take a glance but don't know what to look for and don't feel comfortable discussing their observations with their doctors.

Here are a few diet situations and how they affect your poo:

Anti-Diet: White toast, no fruits or veggies (no fiber)

A lack of fiber causes infrequent, hard stools that require straining during defecation. Fiber, both insoluble and soluble forms, is vital to soften the stool and aid in its effortless passage through the GI tract. Low-fiber diets produce desiccated, pebbly stools and, in severe cases, can result in fecal impaction a condition in which stool forms a rock-hard plug that prohibits passage of any stool at all.

Plant Eater: Steamed broccoli, tofu burger, apple and asparagus

Vegetarians tend to eat well-balanced diets that are high in fiber. The good news is that their stools are frequent (sometimes up to three times a day) and soft in consistency, making trips to the loo satisfying and enjoyable. The downside of a diet high in vegetables is the formation of gas. Because our bodies are unable to digest many of the plant products we consume, these substances undergo fermentation by the bacteria in our colon. The formation of carbon dioxide causes bloating and excessive flatus production but is otherwise harmless. In fact, vegetarian flatus, and feces for that matter, tend not to smell as bad as carnivore-produced waste.

Carnivore's Delight: Big order of prime rib

When red meat gets digested, it produces a class of compound called mercaptans. These are sulfur-containing molecules that lend feces and flatus their rancid odor and account for the general notion that red meat consumption produces a particularly rancid-smelling poo. Another interesting, but now mainly outdated fact, is that consuming red meat before a doctor tests your stool for blood can make it look like you are bleeding. Older stool tests could not differentiate animal hemoglobin (found in red meat) from human blood. Newer, more sophisticated stool tests do not have the same difficulty. Incidentally, population studies have linked diets high in red meat with higher rates of colon cancer.

Plop Plop / Fizz Fizz: Spicy gumbo and jambalaya shrimp, hot chicken wings

Spicy food may taste good going in, but its exit is not always as pleasant. The very last portion of the anal region is lined by the same type of cells as the mouth. This biologic reality means that buffalo wings can sometimes burn just as much on the way out as on the way in. Spicy foods, in general, serve as irritants to the entire GI tract (stomach, small intestine, large intestine) and can speed up the passage of material through the digestive system. The result can be watery stool, occasionally red in color (depending on the ingredients added to the sauce), that exits with a bang I mean a burn.

Fiber Everything: Bran cereal, whole-grain bread, popcorn, black beans, brown rice

Pure bliss. This diet maximizes your chances of achieving "poo-phoria." There is no such thing as eating too much fiber (although you may feel bloated and pass flatus more than the average person). Fiber has the ability to retain water and lends stool its cohesiveness and pillowy softness. It also provides lubrication to the inside of the colon, nourishing colonic cells and creating a friction-free environment for contents traveling down the GI tract. The main caveat here is to drink a lot of water. Consuming fiber without water can actually cause your stools to become harder by adding bulk without moisture.

Celebration Night: Mojitos and cosmopolitans galore (alcohol)

With DADS (Day-After-Drinking Stool), it's liquid in, liquid out. Alcohol is a gastrointestinal stimulant, a direct irritant to the lining of the intestine that speeds up passage and causes diarrhea. Some drinks are worse than others (malt liquor being particularly potent). Stool comes out in liquid form, usually normal in color/smell and occasionally with excess mucus. There is no antidote for the GI tract although drinking clear liquor (such as gin or vodka) may be less problematic and definitely causes fewer hangover symptoms.

Grease Ball: Fries, pizza, bacon, fried eggs and fried chicken (fried foods)

As long as your pancreas, liver, bile ducts and intestines are working properly, fatty foods should be tolerated just fine. Visible fatty/oily stools that smell horrendous, are yellow in color, float on the surface of the toilet, and require multiple flushes usually indicate a problem with fat digestion. Other than that, fatty foods tend to give us a sensation of satiety, or "feeling full." This may be due to release of certain hormones that affect the brain and also to the longer time fatty food remains in the stomach (fats take longer than proteins or carbs to empty from the stomach).

Gulp and Rush: You had a 60-second meal and are always on the run

Eating quickly (depending on what you eat) and/or not chewing completely has very little effect on the stool but can presumably worsen symptoms of acid reflux and indigestion by causing rapid distention of the stomach and refluxing of contents into the esophagus.

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