ìGulpî ñ we do it a few times each day, almost as automatically as breathing. Yet, how many of us know why we devour certain foods while we reject others? And who among us can actually explain exactly what takes place in the alimentary canal, that long tube that begins just beyond our lips, ending at our anus? Well, the science writer, Mary Roach, can, and she does so in a humorous style that will keep you reading, learning and laughing at what she labels ìthe gross parts.îUsing the latest scientific data, Roach goes a step further, peppering her commentary with historic and cultural facts about ingesting and digesting. She begins with our sense of smell, which plays an important role in what types of food or beverage we enjoy. Sensory analysts have long used market research to discover the exact flavors to add to everything, including yogurt, chicken nuggets, ice cream and most other prepared foods. It doesnít make their products any more nutritious, but it sure does keep consumers coming back for more.ìTaste and smell are intertwined in ways we donít consciously appreciate,î and both are affected by cultural factors. Americans love crunchy/salty items but turn their noses up at livestock organs: a fact reflected in our supermarkets, where a whole aisle is devoted to chips and pretzels, while most animal innards are exported. The livers go to Egypt and Russia; the brains and lips to Mexico; while the Philippines gobble up the hearts. Any leftovers are turned into pet food. By the way, whatís considered an acceptable aroma also changes by species, so if you love the smell of a certain brand of cat food, your cat probably wonít!Ah, but people can be easily fooled, Roach writes. Show them a bottle of wine with a fancy label, add a high price tag; and many sommeliers will swear it is an excellent vintage. Thatís why China can pass off barrels of high-priced counterfeit Bordeaux and why a 2011 Gallo cabernet, priced under $10, was pooh-poohed; until a blind tasting held in France ranked it higher than a number of French wines that sold for more than $70 a bottle.Roachís use of quirky facts in ìGulpî is what makes the book so interesting. In the chapter entitled, ìSpit Gets a Polish,î we learn how saliva regulates our bodyís pH levels and begins the digestive process with an enzyme called amylase. Itís one of three digestive enzymes found in laundry detergents and is used to break down starchy stains. She writes, ìLaundry detergent is essentially a digestive tract in a box.î Think about that the next time youíre adding Tide to the washing machine.Next, she tackles the biblical story of Jonah. Can anything survive being submerged in gastric juices? Well, a live oyster can, at least for a few minutes, but all ìhuman-swallowingî survival stories appear somewhat dubious. And exactly how much food does a person need to consume before their stomach bursts like Mr. Creosoteís did in that Monty Python sketch? Roach lets us know.The author of seven books, Roach makes a decent living turning scientific facts into material the general public can understand. Her first book, ìStiff: The Curious Lives of Human Cadavers,î was just the beginning of a string of best-selling nonfictions. Sheís never shy about topics that other writers might consider taboo, including the science behind sex, the facts we never broadcast about space travel and a scientific exploration of the afterlife. ìGulp,î her latest work, taught me more about our digestive system than I ever learned in biology class. My only criticism of the book is her sparse coverage of the small intestine, which acts as a large part of our immune system.Perhaps the most sensational fact Roach reveals in ìGulpî is what really killed Elvis. Funny how dying of a drug overdose can be more glamorous than the truth, but who wants to remember the King as being ìall stopped up?îWhile I wouldnít recommend reading ìGulpî at the breakfast table, it is well worth reading anywhere else. Human biology often contains a gross factor, but no one other than Roach presents scientific facts with such style. Read and learn!
