Trigger Foods

Dinner is over, when suddenly, the waiter emerges with a tray holding rich chocolate torte, carrot cake layered with cream-cheese frosting, and ramekins of perfectly caramelized crème brulée. The guests, who had just thought they were too full to walk to the door, suddenly have room for dessert. This phenomenon is called hedonic hunger, explained Rutgers University in Camden nutrition expert Juliann Nielsen, and it is driven by a complex mix of genetics, emotions, psychological needs, environmental cues, and more. Why do certain foods trigger overeating, and what are the best ways to beat back those cravings?

“When we eat quickly, the stomach is unable to communicate as efficiently to the brain that we have consumed enough to meet our needs,” said Nielsen. “Eating quickly alters levels of ghrelin, the hunger hormone, which plays a role in appetite suppression. The hunger response remains high despite having consumed large amounts.”

A common denominator among trigger foods is that they contain high amounts of sugar, fat, and salt—a combination that is rare in naturally occurring foods. These cravings, Nielsen said, date back to our hunter-gatherer days, when sugar was only available from fruit, while salt and fat were only available from meat. Although these ingredients are now cheap and plentiful, our brains are hardwired to crave calorie-dense foods that kept our Stone Age ancestors from starving when food was scarce.

The food industry knows this fact of human biology and has worked hard to exploit it, Nielsen said. Behind many of our favorite packaged foods, there is a team of chemists, psychologists, technicians, and focus groups exploring different combinations of flavor, texture, aroma, and crunch to arouse our senses and keep us coming back for more. These foods, Nielsen explained, stoke the reward system of the brain and stimulate dopamine, the “feel-good” brain chemical.

“The desire continues to eat this same food again and again,” Nielsen said. “Since dopamine is down regulated—meaning reduced or suppressed in response to a stimulus—the body then requires more and more food to provide pleasure.”

Of course, the reasons for overeating are wide-ranging and abundant. Nutritional deficiencies, mental health, genetics, and even past experiences can all contribute to a tendency toward overeating. Neuropeptides and hormones involved in hunger and satiety are body proteins coded by our individual DNA, which means that these cues are highly bio-individual and become increasingly so as we encounter new foods and eating experiences throughout our lifetime, Nielsen explained.

The bad news? The more often we repeat thoughts and behavioral patterns that lead to overeating, it seems, the more deeply that is imprinted in the brain. Over time, an increase in body fat may lead to an increase in leptin, the satiety hormone. These high levels may result in leptin resistance, with the brain not responding appropriately to register when the stomach is full, Nielsen said.

The good news? That same neuroplasticity allows the brain to alter itself in ways that can help people to become happier and healthier. In other words, the more you reach for healthy snacks, the more you'll crave them, and the less you'll fall victim to hedonic hunger.