The Man Who Ate Everything - Jeffrey Steingarten [67]
Which is why I am pinning my hopes on 180,000 pounds of raw potatoes. Here’s how I figure it.
When food reaches my small intestine, it stimulates cells in the intestinal walls to secrete a class of chemicals known as peptides. Several of these peptides reach the brain, where they turn off appetite and turn on satiety. CCK-8 (short for “cholecystokinin octapeptide”) is one of them, perhaps the most important and certainly the most closely studied. Injecting CCK into the bloodstream or directly into the central nervous system reduces food intake in animals and people and may possibly hasten the burning of body fat. CCK works only after you have eaten something, which leads some researchers to think that it amplifies other satiety signals to the brain.
Hooking myself up to an intravenous bottle of CCK would be extremely inconvenient both at home and in the better restaurants. But how can I increase my body’s own secretion of CCK? Experiments with animals have shown that various amino acids may do the trick, but there’s nothing definite yet. Anyway, I have a more clever method. My own CCK would probably be plentiful enough if it were not foiled by another chemical called trypsin. Like CCK, trypsin is secreted by my small intestine, and for reasons I cannot fathom, it acts as a brake on my production of CCK. If only I could suppress my trypsin.
The cells that produce trypsin do not have a mind of their own. They are slaves to orders sent out from the pancreas. But I am loath to fool with my pancreas, even if I knew how. Besides, merely holding back my secretion of trypsin will not achieve the desired effect. That’s because another chemical, known as chymotrypsin, needs to be neutralized at the same time.
Which is where potatoes come into the picture. A potato naturally protects itself against bacteria and mold by producing substances called protease inhibitors, which prevent these microorganisms from being able to digest the potato’s protein. At least one of them, protease inhibitor II, carries out this lifesaving work by binding to both trypsin and chymotrypsin and neutralizing their effectiveness. If I can only contrive a way to place some protease inhibitor II into my small intestine, my CCK will rise and my appetite will disappear.
I have contrived a way: by swallowing it. Incidentally, if I have somehow given the impression that I figured all this out for myself, I should mention that I learned about the effects of protease inhibitor II from a paper in the journal Physiology & Behavior by Hill, Peikin, Ryan, and Blundell. They added one and a half grams of it to a bowl of soup and fed the soup to eleven subjects right before lunch. The level of CCK in the subjects’ bloodstreams increased by four times only fifteen minutes after they drank the soup and was six times higher another fifteen minutes later. And they ate 17 percent less at lunch than when they drank the same soup without protease inhibitor II. How many days this advantage would last has not been tested.
But my plan to switch to an all-potato diet was foiled by two unhappy facts. Protease inhibitors are destroyed by cooking, and their proportion in the average potato is disappointingly small. To ingest one and a half grams, I would have to eat 500 pounds of raw potatoes before every dinner, the equivalent of 180,000 pounds a year, which would be just as inconvenient as carrying around an intravenous drip of CCK.
It was then that I discovered a company in Des Moines called Kemin Industries, which purchased exactly that number of potatoes a while ago, processed them down to six hundred pounds in an intermediate stage called ammonium sulfate cake, and put them in the freezer. Dr. Christopher Nelson told me that a gram of protease inhibitor II would cost