by Dr. David Ludwig
Today, it’s easier than ever before to get tasty food almost instantly. From drive-through restaurants to frozen dinners, we can satisfy virtually any craving without having to turn on the oven or go near the kitchen. Is all this tasty food to blame for our expanding waistlines?
Some notable public health experts and science writers have eloquently described how the food industry manipulates three basic flavors — sweet, fat, and salt — to make modern processed food virtually irresistible. These exceedingly tasty products, as the argument goes, overstimulate the pleasure circuits in the brain, leading to compulsive eating behaviors. Remember the Lays potato chip slogan, “Bet you can’t eat just one”?
Processed foods are prime suspects in the obesity epidemic. But what’s the evidence that too much tasty food is the actual problem? Must we restrict ourselves to bland fare — typical “diet” foods like baked chicken breast and steamed broccoli — to safeguard against overeating? If so, why do countries celebrated for delicious cuisine like France, Italy, and Japan have notably lower obesity rates than the United States.
Although we tend not to realize it, tastiness (or palatability, to use the technical term) is not an inherent characteristic of food.
True, babies are born with an innate preference for sweet rather than bitter, an instinct that programs them to like breast milk and avoid ingesting toxic substances. However, with appropriate exposure, children outgrow this instinct and learn to appreciate an increasingly wide variety of tastes, such as savory, sour, spicy, and bitter. If this normal maturation process didn’t occur, humans would have starved to death after weaning generations ago.
Food palatability varies greatly among individuals, between cultures and throughout time. Some people love liver, and others hate it. The same is true for blue cheese, oysters, coconut, Brussels sprouts, ketchup, and cilantro. Many Japanese prize aged fermented soybeans (called natto), with its powerful, ammonia-like smell and slimy texture. But some restaurants in Japan refuse to serve this delicacy to Westerners, knowing how they’ll react. Some Asians and Africans used to consuming their traditional diets find American fast food repulsive at first.
Beyond infancy, most food is quite literally “an acquired taste,” determined primarily by our biological responses.
Remember the first time you tried black coffee or stole a sip of beer? They probably tasted awful. But with repeated exposure, the body comes to associate these tastes with the pleasurable effects of caffeine and alcohol. That’s why many adults savor a cup of java in the morning and a brew in the evening. For cake, cookies, chips, and other highly processed carbohydrates, the rush of sugar into the body after ingestion provides the biological reward. The effects also work in the opposite direction. If you eat a favorite treat, say, strawberry cheesecake, and soon thereafter get sick from food poisoning, you might develop an intense aversion to similar foods for quite a while.
Perceptions of a food’s palatability can change rapidly, based on the internal state of the body. Suppose you’ve skipped breakfast and lunch to leave room for a big Thanksgiving dinner. How would that first bite of buttery stuffing taste? But after turkey and all the trimmings, a bit too much alcohol, and much too much dessert, how would you feel about more stuffing?
In long-term studies with humans, the effects of palatability, or tastiness, can be difficult to distinguish from other aspects of diet, but animal studies have been informative. Like humans, rodents have a special fondness for sweetness, especially in liquid form. They dislike bitter-tasting foods and ordinarily avoid them. Rats given free access to solutions of sugar or other carbohydrate in water predictably overeat and become overweight. However, they become equally overweight when the carbohydrate solution is spiked with an intensely bitter chemical, evidently overcoming their instinctive aversion to bitterness. The biological responses to food dominate (and largely determine) perceptions of palatability.
Leaving cost aside for the moment, many people would enjoy the taste of dinner at a fine Italian restaurant at least as much as a meal at McDonald’s. Yet a Mediterranean eating pattern is consistently associated with lower body weight than a fast-food eating pattern. It’s hard to believe that America leads the world in obesity because we have the world’s most delicious diet.
The problem isn’t that we’re getting too much enjoyment from food, it’s that we’re getting too little! Modern industrial foods give us a few minutes of pleasure that soon gives way to hunger and cravings. Luscious, high fat meals will provide pleasure as you eat them and satisfaction for hours afterwards.