Salt Sugar Fat

by Michael Moss

  “Most of the things we love, they love, and most of the things we hate, they hate,” Breslin said. “We both like fermentation, and they love wine, beer, cheese, vinegar, bread. That’s why they are in our kitchens.” Fruit flies also like modest levels of salt in their food. The manipulation of their genes has helped scientists identify the cellular mechanism by which our own mouths detect salt. More recently, Breslin has been studying the flies not for the mechanics of how people taste salt but for clues on why we love it so much.

  It is, after all, just a dumb, white rock that gets dug out of the ground or drawn from the sea.

  Breslin is a food scientist who loves the food he studies and thinks deeply about the food he loves. Like some of his colleagues at Monell, he is not shy about poking the giants of the food industry. His own pet peeves include the low-calorie lines of ice cream that companies make for people who want to lose weight, which Breslin believes only encourages them to overindulge. “I think the interest in making a low-fat, low-sugar ice cream, which is almost oxymoronic as far as I’m concerned, is to allow people to eat four gallons a day,” Breslin said. “That’s not what ice cream is designed for.” He eats ice cream for what it is, a treat to be relished in small amounts. Then again, he has a lean build and seems in control of any compulsions to overeat. His latest infatuation—as a scientist and an eater—was the oil pressed from olives. In its finest, most expensive grades, olive oil will provoke a sting or itch at the back of the throat, which Breslin has been studying for its similarities to the irritation caused by ibuprofen, the anti-inflammatory drug; anti-inflammatory compounds, whether in drugs or foods, may prove to be effective in preventing disease. Friends started sending him expensive bottles—not to test, however, but to consume, because he also discovered that he loved olive oil for its taste. Sometimes he sips it straight, without even a hunk of bread, which only gets in the way of the bouquet.

  What Breslin loves most, however, is salty food. We drove to a Greek delicatessen near his lab to pick up lunch, and ended up gorging on the stuff. The feta cheese was swimming in salt; the spinach pies were loaded too. “You should try one of these so you know what I’m talking about,” he said, pointing to a bowl of cracked green olives. “They’re my all time favorites.” The grocery clerk handed me one, soaked in a garlicky, deeply salty brine that was, indeed, amazing. I could see the joy in Breslin’s eyes when he got one of the olives to taste. “I used to be someone who is borderline hypertensive, and so I was told to worry about it,” he said. “But my blood pressure has been perfectly normal for a long time now, and so I pay no attention to it. I love salty foods. I don’t know if it’s just because of the psychological reward of eating something that’s truly yummy, or if it’s physiological in terms of salt doing something for me. But my personal perception is that when I eat these foods I actually feel better. I don’t mean feel better in that I feel like I’ve been exercising and feel, like, vigorous. I just feel better, like you would feel if you had a small dish of your favorite ice cream.”

  Back in his lab, where we got down to the science behind all that pleasure, it became clear that much about salt’s powers of allure remains a mystery. The very idea of salt inducing feelings of joy seems crazy, given that it is just a mineral, dead and devoid of any sustenance. Sugar and fat, by contrast, come from plants and animals and are loaded with the calories people need to avoid withering away. It makes sense that when scientists slide someone into an MRI scanner and drip a sugary or fatty solution into their mouth, the electrical circuit in their brain lights up and floods them with feelings of pleasure. This stimulus, we know, comes from the part of the brain that rewards us for doing things that keep it alive or perpetuate the human race. Things like eating and sex.

  Salt is not entirely worthless, of course. It does contain sodium, whose importance to our well-being should not be overlooked. In 1940, researchers reported the case of a child who had a condition that diminished his capacity to absorb sodium. He needed massive amounts of salt to survive, and he knew this instinctively. One of the first words he could say was “salt.” At age one, he was licking salt off his crackers. Later, he ate it directly from the saltshaker. His parents and doctors were clueless about his condition, however, and during a prolonged hospital stay, the boy could get only foods that were low in salt, and he died. Even in not so dire a case, a diet lacking sufficient sodium will cause trouble, researchers have found. Rats develop less bone and muscle mass, have smaller brains. Still, most people need only tiny amounts of sodium, which makes it all the more difficult to understand why the vast majority of people are so prone to eating massive amounts of the stuff.

  Part of the explanation for this goes back to the tongue map, the diagram that purports to show that we taste sugar only at the tip of the tongue. Likewise, this same map depicts salt as having a very limited zone—the edges of the tongue, and only toward the front, at that. The map, however, is as wrong on salt as it is for sugar. We taste salty foods like we do sweets, throughout the mouth. “Anyone can demonstrate this for themselves at home,” Breslin told me. “All you have to do is take some lemon juice, honey, cream off your espresso, and a solution of table salt, and stick the tip of your tongue in each of them. You’ll get sour, sweet, bitter, and salty, all on the tip on your tongue, which right there smashes the tongue map.” The taste for salt doesn’t end at the tip of the tongue. People are one big sponge for the salty taste. As there are for sugar, the body has receptors for detecting salt that go all the way through the mouth and down to the gut.

  All this hardwiring for the salty taste would seem to imply that the body wants to make sure it gets a lot of salt. If we were not able to taste it so easily, and if salt were not so alluring, who would be bothered to rummage through the kitchen cabinet for those pretzels? People would stick with the sugary and the fatty. This desire for salt seems to have some grounding in evolutionary history. When everything lived in the ocean, animals had no problem getting the sodium they needed to survive. They wallowed in salty water. On land, however, the early climate was hot and dry. The pre-human mouths that crawled out of the sea may have developed the salty taste receptors as a means of ensuring that their owners didn’t forget about salt when they foraged for food.

  It’s plausible, certainly. But people today aren’t merely remembering salt; they’re devouring it. Thus, the Hungry Man turkey dinner, with its half-week load of salt. Or the popcorn at Yankee Stadium that was so heavily salted one recent afternoon, I had to miss parts of two innings, the first waiting in line for the popcorn and the second getting drinks for my kids to un-kink their throats. The cravings we get for certain foods are a topic that none of the food companies supporting Monell are eager to raise. But Breslin not only freely discusses food cravings, he doesn’t hesitate to link salty foods to an even more dicey subject: drug abuse.

  The notion that some foods behave like narcotics goes back at least twenty years in scientific circles. One of Breslin’s favorite papers was published in 1991, the same year as the saltshaker study. It was written by a professor of psychiatry at the University of Cincinnati named Stephen Woods, who compared eating to taking narcotics. Both, he wrote, pose a considerable challenge to the body’s fundamental goal of staying on an even keel. This balancing trick is known as homeostasis, and eating, like doing drugs, throws things out of whack. “Ultimately whatever you eat ends up in your blood, and our body wants the blood levels of everything—from carbon dioxide to oxygen to salt and potassium and lipids and glucose—to be constant,” Breslin said. “Probably our bodies would be happiest if we could never eat and just somehow magically be able to have some intravenous drip or something that would maintain those things constantly. When you eat, you’re pushing all kinds of stuff into your blood, which goes against the concept of homeostasis, so your body basically responds to that by saying, ‘Holy smokes, what are you doing to me? I have to deal with this now.’ You have to get yourself back to some constant homeostatic level. Insulin is one
of the things you release to push sugar out of the blood and into the cells. This is exactly what happens when you take drugs. When you inject heroin into your body, your body says, ‘Holy cow, what have you done to me?’ It has to try and metabolize these things, and there’s all kinds of coping mechanisms for that.”

  The blood gets especially besieged when processed food is ingested, flooding the system with its heavy loads of salt, sugar, and fat. But where the links between eating and drugs get really interesting is in the brain. There, narcotics and food—especially food that is high in salt, sugar, and fat—act much alike. Once ingested, they race along the same pathways, using the same neurological circuitry to reach the brain’s pleasure zones, those areas that reward us with enjoyable feelings for doing the right thing by our bodies. Or, as the case may be, for doing what the brain has been led to believe is the right thing.

  One of the most intriguing accounts of salt’s effect on the brain appeared in a 2008 paper by researchers at the University of Iowa entitled, “Salt Craving: The Psychobiology of Pathogenic Sodium Intake.” In lay terms, this translates to the craving people get for salt at levels so high it causes disease. The authors reviewed all the brain scanning and other scientific investigations that had been done on salt to date, and they concluded that salt could be lumped with other things in life that become problematic when overdone. Salt, the authors concluded, was similar in this way to “sex, voluntary exercise, fats, carbohydrates and chocolate, in its possessing addictive qualities.”

  For obvious reasons, the word addiction is a particularly touchy subject among food manufacturers. They prefer saying a product is crave-able, likable, snack-able, or almost anything other than saying it is addictive. For them, the term addiction conjures images of strung-out junkies who hold up 7-Elevens at gunpoint for the money they need for another fix. Addiction also raises barbed legal issues that industry is loath to engage. In reality, processed food is so inexpensive and easy to procure that no one need rob a convenience store for a fix—never mind the fact that the convenience store itself, in this case, is the dealer of the fix.

  In 2006 a law firm whose clients included both tobacco and food manufacturers produced a remarkable treatise on the legal fights the processed food industry might face if people tried to hold them accountable for the obesity epidemic. The authors conclude that the food industry overall is in good shape legally, that the strategy used in suing tobacco manufacturers wouldn’t work nearly as well on food manufacturers. But a large section of the report is devoted to the subject of addiction, and the authors labor to identify a strategy that companies could use to persuade a jury that food isn’t addictive. In the end, they don’t deny there are parallels between overeating and drug abuse. They argue, instead, that the word addiction traditionally has had defining qualities, such as the severely painful symptoms of withdrawal, that are not readily applicable to the desire for food. “Labeling the perceived overconsumption of chocolate, for example, as ‘chocolate addiction,’ even if this practice is associated with high levels of comfort (emotional) eating and somewhat unstable eating patterns, risks trivializing serious addictions,” they write.

  Paul Breslin frames the question of addiction a little differently. When people abuse drugs long enough, he noted, the motivation to take more drugs becomes less a matter of wanting the benefit of the drug—the high—and more a matter of wanting to avoid the awful feeling generated by the craving itself. Similarly, when people start feeling hungry, they are not seeking the primary benefit of food, the calories needed to keep them alive. Rather, they are responding to the body’s signal that it does not ever want to be put in the position of needing to eat. Most people in America never feel true hunger pain, the gut-wrenching result of being starved for nutrition. Consider how often people say they feel hungry during a single day, Breslin said. “With few exceptions, we can go a day without food or water with no problems whatsoever. The body has enough calories. But people who fast for a day feel awful. Your body comes to expect that we will feed it, and it has all these mechanisms in place so if you don’t do it, then you start to feel awful. Ultimately you end up feeding yourself in order to feel okay.”

  This notion that we eat not so much for pleasure as we do to ward off an awful feeling, reminded me of the work done by Howard Moskowitz, the legendary food scientist who engineered the new flavor for Dr Pepper. In the study he dubbed “Crave It,” he found that people are drawn to foods that are heavily salty, sweet, or fatty for reasons other than hunger. They are drawn to these foods by emotional cues and the wish to avoid the lousy feeling that the body generates as a way to defend against starvation. The fear of hunger is deeply rooted, and food manufacturers know well how to push the buttons that evoke this fear. (A particularly stark example of this comes from the Mars company in promoting its Snickers candy bar, which won applause from the advertising industry with this slogan: “Don’t let hunger happen to you.”)

  As bad as the word addiction may be, however, the food industry has another problem when it comes to salt—one that could prove to be more problematic. In assessing the industry’s culpability for the epidemic of overeating, scientists have come up with evidence that the manner in which people have come to crave salt, rather than the craving itself, is far more damning.

  As it turns out, the manufacturers of processed foods have been creating a desire for salt where none existed before.

  Babies love sugar the instant they are born. Simple experiments have demonstrated this, by eliciting smiles with a droplet of sugary water. But babies do not like salt. They don’t like it at all until they are six months or more into their lives, and even then, they have to be coaxed.

  This idea that salt is being pressed upon America’s kids comes from the scientists at Monell, who have been pushing hard to pinpoint the genesis of our taste for salt. They wanted to know what caused kids to like salt, if it wasn’t a natural thing for them to do. So they followed sixty-one children, starting at infancy. First, they surveyed their parents to learn how much salt the kids got in their diets, and the kids fell neatly into two camps: One group was eating what their parents ate, salty cereal and crackers and bread made by food manufacturers, while the other got baby foods that had little or no salt, like fresh fruits and vegetables.

  Then the Monell researchers tested the kids to see if there was any difference in how much the two groups liked salt.

  The results were published in 2012 in the American Journal of Clinical Nutrition, and they kicked up quite a stir among regulators and food industry officials. To test the kids’ fondness for salt, the Monell investigators, led by Leslie Stein, gave them solutions of varying salinity to sip, starting when they were two months old. At that age, all the kids either rejected the salty solutions or were indifferent to them. At six months, however, when they were tested again, the kids split into two groups. Those who had been given fruit and vegetables to eat still preferred plain water to the salty solutions. But those who had been fed foods that were salty now liked the salty solutions.

  Over time, the two groups—the salted and the unsalted—grew even more disparate. “Mothers reported that preschool-age children who had been introduced to starchy table food by six months of age were more likely to lick salt from the surface of foods,” the study said. “There was also a trend for these children to be more likely to eat plain salt.”

  Of course, the kids didn’t have to resort to the shaker. By preschool, the salted kids were getting foods from throughout the grocery store that were loaded with salt—potato chips, bacon, soup, ham, hot dogs, French fries, pizza, crackers.

  When the study was released, Gary Beauchamp, the center’s director and a co-author, talked about its significance. These were kids being studied, he stressed. Kids who were not born liking salt. They have to be taught to like the taste of salt, and when they are, salt has a deep and lasting effect on their eating habits. “Our data would suggest that if one wants to reduce salt in the population as a whole,” Be
auchamp said, “then it’s important to start early, because infants and children are very vulnerable.”

  With this revelation, the industry’s heavy use of salt moves from the realm of merely satisfying America’s craving for salt to creating a craving where none exists.

  As it happened, I wasn’t the only one who needed help from the experts at Monell to understand the powers of salt. In 2005, when Washington put a scare into the industry by urging people to slash their intake of salt to less than a teaspoon each day, some of the largest food companies convened a group they called the Salt Consortium to figure out a way to deal with this threat to their industry. The group kept its existence confidential for fear of generating unwanted attention, but I learned about it from food company officials who also divulged that they had chosen none other than Monell to gather the facts to help them out of their predicament.

  The group’s goal was to learn precisely what made salt so alluring, so that they might find ways to reduce its presence in their products. As with sugar and fat, the industry has a strict bottom line on reducing salt: This effort can’t hurt their sales in any way. Their products, with less salt, have to be just as alluring as they are in full-salt mode.

  But the more the industry looked at salt, the more it realized that the consumer was only part of the problem. The manufacturers themselves were utterly, inexorably hooked on the stuff. Each year, food companies use an amount of salt that is every bit as staggering as it sounds: 5 billion pounds.