Your Body: The Missing Manual

Chapter 8. Your Digestive System

Glamorous it isn’t. But stretching from your lips to your anus is a 30-foot-long, mucus-lined hose that converts a perfectly appetizing meal into the all-too-familiar brown sludge.

Talk about it in public, and you’ll quickly lose your dinner companions. That’s because few people—aside from late-night comics or a roomful of toddlers—want to know what really became of yesterday’s lunch. Oh, we may open our mouths to toss in a tasty morsel, but when it comes to talking about what happens next, our lips are sealed. And we certainly don’t want anyone in a white coat messing around in there either, whether it’s a dentist poking in the front end or a colonoscopist heading up the back.

That’s unfortunate, because a proper understanding of your body’s food-processing system can save you a good deal of embarrassment. For example, knowing your plumbing can help you fight bad breath, disarm heartburn, and ensure that everything you eat keeps moving steadily along. Most important, it gives you valuable insight into the nutrients you need in your diet and the troublemaking substances you should avoid.

In this chapter, you’ll travel down your long, snaking food canal. You’ll watch as your digestive parts—mouth, stomach, intestines, and everything in between—grind food to a fine paste and mix it with a powerful assortment of food-dissolving substances in the never-ending chemistry experiment we call digestion. On the way, you’ll learn some of the secrets to proper ...