Salt Sugar Fat: How the Food Giants Hooked Us (24 page)

Twenty-four centuries later, fat is seen as one of the most potent components of processed food, a pillar ingredient even more powerful than sugar. As Aristotle pointed out, fat is indeed oily, in some of its forms. Canola, soy, olive, corn, and the other oils are all liquid fats, viscous and flowing, easily spotted and identifiable as fat. In other cases, fat in our food is a solid at room temperatures, and not readily recognized. A hunk of cheddar cheese is one-third fat, along with protein, salt, and a little sugar, and even that statistic understates the force that fat brings to food. Two-thirds of the calories in that cheese are delivered by the fat, which packs more than twice the energy of sugar.

When it comes to divining the allure that it brings to food, however, the taste of fat is a bit harder to pin down. It is not part of our official roster of primary tastes, which currently consists of just five members: sweet, salty, sour, bitter, and a more recent addition known as umami, which is a meaty, savory taste derived from an amino acid called glutamate. Some food researchers have argued for adding fat to the list of five primary tastes, but they face one substantial hurdle:
The entry rules for this group requires that scientists know how each taste interacts with our taste buds, and no one has yet figured this out when it comes to fat. All the other tastes have receptors in the taste buds that have been identified and labeled as their hosts. It is through these receptors that the sweet taste and other flavors get delivered to the brain.

No such receptor for fat has been found.

And yet, because of fat’s remarkable powers, the processed food industry relies on it like no other component. Fat turns listless chips into crunchy marvels, parched breads into silky loaves, drab lunchmeat into savory delicatessen. Like sugar, some types of fat furnish processed foods with one of their most fundamental requirements: the capacity to sit on the grocery
store shelf for days or months at a time. Fat also gives cookies more bulk and a firmer texture. It substitutes for water in lending tenderness and mouthfeel to crackers. It lessens the rubbery texture in hot dogs, deepens their color, keeps them from sticking to the grill, and, as an added bonus, saves the manufacturers money, since the fattier trimmings of meat they use in making hot dogs cost less to buy than the leaner cuts. Indeed, the entire hamburger industry—which turns out seven billion pounds or more of ground beef each year—revolves around fat. Hamburger is a mixture of beef carcass trimmings that are purchased from slaughterhouses throughout the world, based on their fat content. The fattiest scraps are called “fifty-fifties,” as in half fat and half protein, and these are mixed and matched with less fatty cuts, like “ninety-tens,” to achieve the desired fat level in the final ground beef. When retailers like Walmart place their orders for ground beef from the meat companies that make the hamburger, they do so by specifying the fat content, which ranges between 5 and 30 percent. Surprisingly, fat is even the key determinant of the nutritional value of ground beef. The Department of Agriculture has a handy online calculator, and depending on the percentage of fat that is entered, the levels of calcium, niacin, iron, and other elements in the meat go up or down—as do, of course, the loads of saturated fat, which is the type of fat associated with heart disease.

Fat also performs a range of culinary tricks for food manufacturers, thanks to another of its extraordinary powers. It can mask and convey other flavors in foods, all at the same time. This can be seen in a dollop of sour cream, which has acidic components that, by themselves, don’t taste so great. Fat coats the tongue to keep the taste buds from getting too large a hit of these acids. Then, this same oily coating reverses direction, and instead of acting as a shield, it stimulates and prolongs the tongue’s absorption of the sour cream’s more subtle and aromatic flavors, which, of course, is what the food makers want the taste buds to convey to the brain. This act of delivering other flavors is one of fat’s most valued functions.

Fat has a final trait, however, that makes it even more essential than sugar in processed foods. Fat doesn’t blast away at our mouths like sugar
does; by and large, its allure is more surreptitious. As I spoke with scientists about the way fat behaves, I couldn’t resist drawing an analogy to the realm of narcotics. If sugar is the methamphetamine of processed food ingredients, with its high-speed, blunt assault on our brains, then fat is the opiate, a smooth operator whose effects are less obvious but no less powerful.

A
ristotle’s observations in taste were all the more remarkable given how poorly he actually understood the mechanics of the human body. He rejected the concept of the brain as the mind’s organ, which his teacher Plato had embraced, and chose instead to view the brain as a regulator of the heart’s temperature. The heart, by his estimation, played the starring role in matters both physical and psychological; some scholars believe he even saw the heart as the primary organ of taste, with the tongue a mere facilitator. Today, of course, scientists are turning to the brain to understand the allure in food and our ability, or lack thereof, to control our consumption. Some of the more intriguing studies on this subject have emerged from Oxford University in England, where a neuroscientist named Edmund Rolls has been investigating, to put it broadly, how the brain processes information. Rolls is not a food scientist, though some of his work on the brain’s role in thirst and appetite has been funded by Unilever, the global food giant based in England. Rather, he roams widely through the field of brain research, using medical imaging machinery to monitor the brain’s responses to various stimuli. In 2003, he published on the
results from an experiment in which he charted the brain’s response to two substances: sugar and fat.

It was already well established that the ingestion of sugar will light up the nucleus accumbens and other areas of the brain that are collectively known as the reward centers, generating intense feelings of pleasure when we engage in acts of self-preservation like eating. Sugar’s effect on the brain is so strongly and consistently exhibited in these studies that some scientists have come to see certain foods as potentially addictive. At a federal
research facility in Long Island called the
Brookhaven National Laboratory, scientists have studied the brain’s reaction to processed foods and drugs like cocaine, and have concluded that some drugs achieve their allure, and addictive qualities, by following the same neurological channels that our bodies first developed for food. Where the Brookhaven scientists used foods that were sweet, or both sweet and fatty, in their studies, Rolls wanted to know whether fat
alone
had the same narcotic-like affect on the brain.
He recruited a dozen adults, healthy and mildly hungry, having not eaten for three hours. One by one, they entered the tunnel of a functional magnetic resonance imaging machine, or fMRI. Once inside, they couldn’t move their arms, so plastic tubes were placed in their mouths, through which they were fed a solution of sugar and another solution of vegetable oil. Purchased at a local supermarket, the oil was made from rapeseed, also known as canola, and came fully loaded with fat in all three of its basic modes: saturated, monounsaturated, and polyunsaturated. In addition to the sugar and fat solutions, a third served as the control by mimicking plain saliva.

As they tasted and swallowed, Rolls watched the machinery register their brain’s response. As expected, the saliva generated no evident stimulus. No surprises with the sugar solution, either: It provoked a vivid response, with the images generated by the machine depicting the brain’s electrical activity as patches of bright yellow. But the shock came when his subjects got hold of the fat: Their brain circuitry lit up just as brightly for the fat as it did for the sugar. Moreover, the images showed that this brain activity occurred precisely where neuroscientists would expect to see this activity. The sugar and fat stimulated areas of the brain associated with hunger and thirst, but they also lit up the reward center, which generates the feelings of pleasure.
“Fat and sugar both produce strong reward effects in the brain,” Rolls said when I asked him which was more potent, sugar or fat. It’s a toss-up.

In recent years, some of the world’s largest food manufacturers have been conducting brain research of their own to assess the depths of fat’s allure. Unilever alone invested $30 million on a twenty-person team that
used brain imaging and other advanced neurological tools to study the sensory powers of food, including fat. The scientist who led the Unilever team until recently, Francis McGlone,
described its operations as a freewheeling exploration of a rapidly expanding corner of science, where $3 million brain scanning devices and other neurological testing can reveal more about consumer likes and dislikes than companies could ever glean from focus groups. Unilever has a massive lineup of health and beauty aids, from Dove to Alberto VO5, as well as packaged food, from Ben & Jerry’s to Knorr, and McGlone roamed across the whole range of products hunting for ways to improve upon them. For the most part, he sought to discover precisely what made certain groups so alluring. Like many specialists in basic science who go to work for food manufacturers, he brought with him the dispassionate language of researchers who see consumers as experimental subjects.
“I went there to build a research focus that looked at the reward-based systems that underpin their business,” he told me. “Their business was basically all feeding and grooming, involving 6.7 billion people or, in my view, 6.7 billion primates. And I saw feeding and grooming as very stereotypical human behaviors. There is not a lot to be gained from asking people
why
they like something, because they don’t bloody know. These are very low-level processes that drive these fundamental behaviors, and I’d gotten into imaging because it’s a good way to sort of bypass the mouth, if you like, so you can see just what the neural processes are underpinning a behavior.”

McGlone didn’t have to bother talking to his subjects; he could peer into their brains. And the discoveries made by his team underscored the complex and varied ways in which processed food can be made ultra-alluring. They explored all five of the basic senses. To examine the
role that odor plays in foods, for example, they let their subjects smell a glass of Hershey’s Chocolate Cookies ’n’ Cream Milkshake, and found this excited the brain’s pleasure zones just as if they were tasting the drink. To study
the power of hearing, one of the team’s scientists, Charles Spence, amplified the sound made by potato chips when they were eaten. This study—which won an Ig Nobel, the prize awarded to research that is brilliant but
quirky—showed that the louder the noise, the deeper the allure; the noisiest chips were rated by test subjects as the freshest and crispiest. McGlone has studied how the mere sight of food can excite the brain.

Being the world’s largest ice cream maker, with brands like Breyer’s and Ben & Jerry’s, Unilever itself got quite excited by his work on how the brain responds to the silky smooth fat and sugar in ice cream. This project started in 2005 when
McGlone had a conversation with the company’s research director for consumer insight. They determined there might be a substantial commercial payoff if he could establish that ice cream made people happy—through scientific methods, that is. So McGlone put eight graduate students in an MRI and then scanned their brains as an assistant tipped a spoon of vanilla ice cream onto their lips, letting it melt into their mouths. McGlone is a bit sheepish about the scientific weight of this experiment: He told me that he would never seek to publish the results, since there were too few subjects and
too many variables to qualify as solid, peer-reviewed science. But the resulting images—which show the brain’s pleasure centers lighting up as the subjects tasted the Unilever ice cream—thrilled the marketing arm of the company. “This is the first time that we’ve been able to show that ice cream makes you happy,” a Unilever vice president, Don Darling, told a food industry publication.
“Just one spoonful of Carte D’Or lights up the happy zones of the brain in clinical trials.” Unilever released the results, generating a flurry of publicity for the company and its ice cream in news reports throughout the world including the U.S. media with the slogan: “Ice Cream Makes You Happy—It’s Official!”

Even without these brain studies, however, food manufacturers have long understood the power of fat to make their products more attractive. The industry’s reliance on the stuff runs so deep that suppliers of fat, like Cargill, hold training seminars. Based near Minneapolis,
Cargill is one of the world’s largest privately owned companies and a dominant provider of ingredients to food manufacturers. It sells seventeen types of sweeteners, forty types of salt, and twenty-one oils and shortenings, from coconut for spraying on snacks to palm for candies to peanut for deep-fat frying. In a
recent presentation to food manufacturers who purchase its fats, a Cargill manager empathized when a customer asked for advice in reducing the amount of fat that snacks absorb in being fried.

Lessening the amount of fat in processed food—like reducing the sugar or salt—is no simple matter to the manufacturers. They can’t allow this to diminish the taste or texture, or they will lose sales. Nor can they let a reduction in fat cause their production costs to rise too high, or they will lose profits. The X factor is often how much more money consumers are willing to spend for a healthier product. In this case, the Cargill manager pointed out, fiddling with the fat used for frying had serious implications for the bottom line of its customers. Sure, they could cut down on the fat in their foods. All they had to do was turn up the temperature of the oil. But the higher the temperature, the less often the oil can be reused before going bad, which would send the food manufacturers running back to Cargill more often for fresh oil. “It doesn’t work all of the time, but the hotter the oil, the less absorption of the snack, in principle,” the manager, Dan Lampert, said. “We like it because the hotter the oil, the more oil we sell. Just kidding.”