Craving Sugar
The most common dietary preference is a sweet tooth. There’s a good evolutionary reason for this. When food was scarce, it compelled early humans to look for foods that gave instant energy. And the sweet fruits that fit the bill came bundled with lots of other great nutrients. Today, of course, food, particularly sweet food, is more than plentiful—and the sweet tastes we love are often stripped of other beneficial nutrients; that we’re genetically predisposed to prefer sweets frequently undermines our efforts to eat more nutritiously.
The evolutionary survival advantage conferred by sugar is one reason why taste buds for sweetness are concentrated front and center on the tongue, where the greatest amount of food tends to land and, bud for bud, are most prevalent. Every time they get activated, they quickly fire off a response to the brain that stimulates feelings of pleasure. Enjoy sweets. But just as your nose gets used to the odor of perfume a few minutes after you sprayed it, your taste buds quickly adjust to the sweetness, losing their sensitivity and requiring more and more to reach that same “reward” level of activation.
This is part of the reasoning behind Guideline 1 in chapter 9: eat delicious food. Nature has you hard-wired to enjoy those first few bites the most. Once you’ve gotten some initial calories, it tones down the biological reward feedback system. Unfortunately, most people ignore that signal and keep eating, even though they’re not receiving the same pleasure from the food. If, on the other hand, you pay attention when you’re eating, your body subtly nudges you to stop while you’re ahead.
There’s another reason many people are drawn to carbohydrate-rich foods like sweets: Carbs increase the ability of the amino acid tryptophan to travel into the brain, where it is converted into serotonin. Serotonin is a powerful hormone that helps stabilize your mood, supports restful sleep, and reduces the risk of depression. Some people theorize that carbohydrate craving may reflect a drive for emotional stability. While tryptophan is found in protein-rich foods—turkey, for instance, is an abundant source—there it competes with other amino acids to get into the brain. Carbohydrates, however, spark the release of insulin, which pushes the other amino acids out of the bloodstream, leaving tryptophan behind. Competition gone, tryptophan can sail into your brain.
A switch to more wholesome carbohydrates (think real food, not processed stuff!) still provides the serotonin benefits, just without the empty calories of excessive sugar or the high-glycemic carbohydrates.
The Allure of Fat
Sugar is on the menu when we need fast calories, but we are also genetically programmed to search out fat, since it provides more calories with less food. Although the research is not conclusive, we probably don’t have taste receptors for fat; what draws us in is the texture and “mouth-feel” it brings.
Fats may also act as a mild sedative. There is some indication that calorie-dense foods such as fats trigger the adrenal glands to reduce their release of stress hormones, thus making us feel calmer. If this is true, it’s not surprising that many think of ice cream as a comfort food!
Despite the rhetoric, fat is not the monster it’s made out to be. Sure, it comes bundled with lots of calories, but it also has a lot of other beneficial traits. For instance, it contributes to the feeling of fullness. That’s why low-fat and fat-free, sugar-based snacks leave you hankering for more calories. You also absorb more nutrients from certain foods like vegetables when your meal includes some fat, probably another reason why we’re biologically driven to crave fat.
For instance, one research study compared participants who ate a fat-free salad to those eating a salad with half an avocado (rich in monounsaturated fats).
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The avocado eaters absorbed about ten times the carotenoids (powerful plant chemicals that help protect us from a variety of biological ills) from the salad’s greens than the fat-free eaters. Meanwhile, adding avocado to salsa more than quadruples the amount of lycopene you absorb, another important phytochemical that can significantly reduce the risk of heart disease and prostate cancer, among other conditions. Other studies comparing people eating salads with fat-free dressing to those eating salads with traditional dressings find similar results.
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Fat also confers other qualities onto food, such as carrying flavor molecules. Cook an onion in water and it’s much less flavorful than if you sauté it in oil. The oil brings the onion’s flavor molecules to the surface, making them more accessible to your senses. Fat also allows you to cook at high temperatures—think deep-frying—providing an appealing crunchy texture to food.
The key to dietary fat, then, is moderation—not avoidance. Don’t buy in to the hype behind the low-fat mantra. There is little research to support strong links between dietary fat (including saturated fat and cholesterol) and heart disease, cancer—and even body f at.
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As researchers from the Harvard School of Public Health, who used to be among the chief recommenders of a low-fat diet, proclaim, “It is now increasingly recognized that the low-fat campaign has been based on little scientific evidence. . . .”
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Sugar + Fat = Heaven
Okay, so you’ve got your predisposition for sugar and your predisposition for fat. Put the two together and the sum is greater than the parts. In fact, research shows that a 50/50 ratio of fat to sugar stimulates the greatest rush of feel-good chemicals called endorphins.
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Turns out, that’s exactly the proportion found in high-quality chocolate. No wonder chocolate remains the single most craved food in the world!
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It is particularly highly craved by women, and even more so in the days just prior to menstruation. That’s because eating a chocolate bar is not unlike a visit to the drugstore. Not only does it contain caffeine and a related energy-inducing compound called theobromine, but it also contains phenylethylamine, which acts like an opiate. Together, the three chemicals can pull a woman out of that premenstrual fatigue/mood swing, back into something approaching normal.
Premenstrual Cravings
Women can often predict the onset of their period just based on the food cravings they experience within the days leading up to the actual bleeding. They’re not imagining things. Just before a woman’s menstrual period, estrogen levels suddenly drop. This leads to those classic premenstrual symptoms of water retention, irritability, moodiness, and food cravings.
One option? Choose foods to minimize those symptoms. For instance, fatty foods increase estrogen levels while low-fat foods and fiber decrease levels. So, if you typically follow a high-fat/low-fiber diet (like most Americans), you likely have higher estrogen levels throughout the month. When that drop comes, it’s more precipitous for you. On the other hand, a lower-fat/higher-fiber diet maintains lower circulating levels of estrogen. Thus, when the premenstrual drop occurs, it’s not as severe. The result? Fewer premenstrual symptoms, including food cravings .
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Context Matters
How you feel about food also plays a large role in how that food tastes.
Numerous studies find that our preconceptions, ideas, and attitudes, and the context food is consumed in, can actually change the flavor of foods. Chunky green split pea soup may appeal to a blindfolded taster, but taste awry when that same person eyes a bowlful. And research shows that people rate brightly colored foods as tasting better than bland-looking foods, even when the flavor compounds are identical. Food manufacturers know this. Butter is rarely naturally yellow; it’s dyed yellow to be more appealing.
One study had participants eat steak and French fries in a room with special lighting. In that setting, the food appeared to be a normal color, but when it was revealed that the steak was blue and the fries green, some participants became ill.
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Color can even fool our taste buds into perceiving taste differences where none exist. In one study, researchers changed the sweetness and color of orange juice in various increments, finding participants experienced more difference in taste between the same juice of different colors than between juices with different levels of sweetness.
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Of course, brand marketing also makes a difference. Put a carrot in a McDonald’s wrapper and kids will tell you it tastes better than carrots served in a plain wrapper.
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I expect that it’s not too hard to accept that the same food can taste dramatically different when eaten in different circumstances. Just imagine the difference that results from eating an ice cream sundae as part of a birthday celebration compared to one consumed stealthily in the middle of the night. Chianti sipped with your lover on a romantic Tuscany hillside pleases your palate in a way that you’ll never reproduce if you’re gulping it at the kitchen table while spooning strained peas into your one-year-old’s mouth.
Culture and attitude play a large role in our preferences: A delicacy like candied grasshoppers may not be highly valued outside of Mexico, nor would termite cakes be as appreciated as they are in Liberia. And how many Americans relish roast dog, a traditional favorite in Samoa?
Food also tastes different depending on the foods it’s paired with. For instance, if you eat a piece of cheese before sipping a glass of wine, the wine tastes smoother because the cheese’s fat and protein molecules coat your taste receptor cells so the acidic wine molecules can’t connect with them.
The same type of process is at work when you eat artichokes. They contain a chemical called cynarin, which suppresses sour and bitter taste receptors. So any food you eat after the artichoke tastes sweeter.
The flavoring monosodium glutamate (MSG) is highly used because it excites taste receptors, so you need less of a particular taste to fully activate the receptor. In other words, MSG enhances the way food tastes, making it a cheap solution to improve the flavor of low-quality ingredients.
Bottom line: You need to experiment more with your food. Maybe you don’t like veggies because they’ve never been prepared the right way. Maybe you don’t like certain foods because of your attitude toward them. Maybe you aren’t eating foods with the right accompaniments.
When you change what you eat, eventually your preferences catch up to accommodate your new diet. For instance, the more salty foods you eat, the more salt you need to enjoy the food.
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This is due in large part to your taste buds adapting to a higher salt content and then needing it for stimulation. But taste buds only have about a three-week lifespan. So if you switch to lower-sodium foods, after three weeks you’ll find you stop reaching for the salt shaker during every meal. Then try eating something very salty that you previously enjoyed. You’ll find it no longer appeals.
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Research shows this method also works with sweet and high-fat foods.
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Not only can you change your taste buds by revamping your diet, but since consuming lots of high-sugar and high-fat foods alters brain neurochemicals involved in appetite and reward,
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reducing your consumption of those foods essentially rewires your brain to adapt to your new diet, inducing cravings for this new way of eating.
Be persistent. If you don’t like broccoli, don’t write it off entirely. Try it different ways: steamed with a bit of butter and nutmeg; sautéed with olive oil and garlic; roasted with Parmesan cheese. As mentioned earlier, research shows that repeated exposure increases people’s enjoyment of certain foods. Most people don’t like coffee when they first taste it, but many develop a love for it over time.
Putting Meat in Its Place
Suppose you’re considering eating less meat. How do you do it? I’m not talking about going vegetarian or vegan, just cutting back a bit. If you’re used to the typical American style of eating, you’re accustomed to meat at the center of the plate, and it may be difficult to conceive of it otherwise.
The arguments for eating less meat are extensive and well established, whether you are considering your personal health or that of the environment and the world community. It’s really not as difficult as many people believe. Rest assured, for example, that there are no physical withdrawal symptoms: No jittery feelings, no headaches, no tiredness. You may get cravings, perhaps, but that’s okay. Because remember, there’s no need to go all out: You can feed those cravings.
Here’s some food for thought on reducing the meat habit:
First, know this up front: The typical concern about getting enough protein is unwarranted. We’ve been programmed to think of meat as an essential protein source. But it’s not. Plants have plenty of protein. In fact, calorie for calorie, many plant foods contain more protein than animal foods. Besides, most Americans get way more protein than is recommended anyway (probably twice as much, according to USDA records). Unless sugary snacks predominate in your diet, protein is not a concern. (And if you are a sugar junkie, expanding your horizons is good general advice; adequate protein is just one of many concerns to consider.) Nor do you have to worry about getting the essential amino acids. It happens naturally with just a little bit of variety, which again, is good general advice. The typical conception that you need to be well-educated to reduce the meat habit (or even dump it entirely) has long been disproven.