First Bite: How We Learn to Eat by Bee Wilson

it backward , or retronasally. The hundreds of chemical compounds that go together to make up the flavor of a particular blend and roast of coffee travel to the backs of our mouths and sneak through the nasopharyngeal passage into the nasal cavity. As we sip and swallow, we are not conscious that the splendid flavors—the nuttiness of the roast, the notes of cherry and peach—are created in the nose, not the mouth. This spectrum of retronasal joy is lost to anosmia sufferers. All they have left is the harsh and basic tongue-notes of sweet, sour, bitter, and salty. Like Abi Millard enjoying a salty gammon steak, anosmia sufferers often seek out extremely salty or sweet foods to compensate for the loss of flavor.
    Anosmia is a surprisingly common problem—as many as 2 million people in the United States have some form of smell or taste disorder. It is not a trivial disability. The ability to pick out the jasmine aroma in a cup of espresso, or to spot the difference between grapefruit and pomelo, might seem of little importance to anyone except food writers. But medicine and neuroscience are now starting to recognize that anosmia can be an extremely traumatic condition, and not just because of the danger in emergencies of not detecting the smell of smoke or gas. Sufferers often end up depressed and malnourished. Without flavor, the motivation to eat is lost. When nothing can be smelled, there is a yearning for familiar tastes that can never be satisfied. Christmas goes by without the background aroma of turkey or spice; summers are no longer marked by the perfume of strawberries and cut grass. Sufferers often describe it as a deep loss. Duncan Boak, the founder of Fifth Sense, who became anosmic after a head injury, said that he feels as if he were looking at life through a pane of glass.
    Part of what is missing for the anosmia sufferer is the safe place of childhood, a place to which the rest of us can return whenever we eat the foods we have always loved. A couple of years after the accident, Marlena Spieler found that glimmers of her former responsiveness to flavor werereturning. Depending on the level of damage to the brain, some anosmia sufferers do recover. Marlena slowly trained herself to love chocolate again, starting with the blandest milk chocolate and working up to 70 percent cocoa solid dark chocolate. Occasionally, her morning coffee gave her pleasure rather than just blankness. We met for lunch at an Italian restaurant and she seemed to be doing well, exclaiming over the blood-orange slices in our cocktails and nibbling on a deep-fried sage leaf. But even as her flavor perception was improving, she continued to feel unsettled. It wasn’t just that food tasted bad. It was that—she told me—she no longer felt quite “like Marlena.” As she explained to the BBC Radio 4 Food Programme, our sense of taste is something that anchors us to the person we have always known ourselves to be: “Your world has a certain taste. Your mother makes something a certain way. You’re used to certain flavours in your life and if you take that away, you start saying, ‘Who am I?’”
     
    Memory is the single most powerful driving force in how we learn to eat; it shapes all of our yearnings. Sometimes the memories are very short-term ones—for instance, whether or not we’ve just eaten. In one study, when a profoundly amnesiac patient was offered another meal only minutes after he had completed the first, he willingly took it. Minutes after that one, he ate a third meal. Only when a fourth meal was offered did he refuse, telling the experimenters that his “stomach was a little tight.” This suggests that having a conscious memory of our last meal matters as much as hunger in determining how much we eat.
    For most of us, though, the food memories that really matter go much further back. You may not be able to remember what you had for lunch last Tuesday, but I bet you can recall the habitual meals of childhood, the