Brain scientists identify a new kind of hunger that makes us overeat

Stephanie Walden | for Bright Line Eating

Imagine sitting down to a massive dinner spread: a huge pot roast, perhaps, complete with a smorgasbord of side dishes and, for good measure, a pie for dessert. After eating such a meal—let’s call it a 1,200-calorie dinner—you’re stuffed…right?

At least, you’re supposed to be stuffed. But some people experience a nagging urge to keep grazing, even after overindulging. For these people, the next move is to head to the couch and pop open a bag of chips. And then, they go back to the fridge for a second slice of pie.

From a logical perspective, this behavior makes little sense. Most people are well-versed in the dangers of obesity, which causes a slew of health issues and even early death. And yet, some people still hear that voice in the back of their heads, pushing them to keep eating when their stomachs are stretched to the limit.

Dr. Susan Peirce Thompson, professor of Brain and Cognitive Sciences and author of the New York Times best-selling book, Bright Line Eating, coins the term “insatiable hunger” for this phenomenon. Insatiable hunger is characterized by two main attributes: it’s not satisfied by eating, and it’s often associated with a desire to stay sedentary.

This is at odds with how humans are biologically programmed. Back in the hunter-gatherer days, people experienced hunger differently. When the berry bushes were heavy with fruit, or there had been a successful hunt, the whole village would gorge on calories with the expectation that it might be days until the next meal. This massive caloric intake was accompanied by an urge to get active—to go find a mate, build a hut, or head out in search of the next source of protein. In other words, we were cued to put those calories to use for activities linked to survival.

Humans were also programmed for something called “compensation,” which is the brain’s regulatory mechanism for preventing the accumulation of excess weight. With compensation on board, if you eat one large meal in the morning, you’re naturally inclined to eat less for the rest of the day. Parents of young children may recognize this phenomenon in their kids who, after eating a big lunch, will respond by marginally picking at dinner.

But recent studies show that 70 percent of adults have lost the ability to naturally compensate for the calories they ingest. And, more worryingly, a significant number of people experience a “bell curve” of hunger: they’ll report diminishing hunger halfway through an eating session, but by the end the meal, they feel the same or even higher levels of hunger than when they sat down.

One of the culprits of this is the modern diet, whose hallmark is calorie-dense, nutritionally-barren foods. In fact, up to 80% of the calories in the average American grocery store contain added sugar. This is a far cry from the fiber- and protein-rich diets our brains adapted to millennia ago.

“Now we can eat a doughnut and a drive-through coffee concoction and consume half of our daily caloric needs, while barely filling our stomach,” Dr. Thompson says in her best-selling book. “Volume of food and calorie consumption are no longer correlated the way they once were.”

In the same chapter, Dr. Thompson illustrates an average American’s relationship with food, examining how it is diametrically opposite from the habits of primitive man: “Think of our modern activities—eating in front of the TV, eating while reading a book, eating while checking email or surfing the web, eating at a sporting event, eating at the movies, eating in our cars… We have turned life into a continuous, sedentary buffet.”

Here’s what’s going on in our brains when we eat this way.

When fat cells expand, they release a hormone called leptin. Leptin is responsible for telling our brains to stop eating because there’s enough fuel on board. It’s also the hormone that gives us the urge to put those consumed calories to active use.

But today’s processed flour- and sugar-laden diets cause insulin levels to skyrocket. In fact, over 50% of adult Americans have Type II Diabetes or pre-diabetes from chronically elevated insulin. And in 2005, researchers discovered that elevated insulin blocks leptin from effectively reaching the two parts of the brain it’s meant to impact: the hypothalamus, which governs eating, as well as survival metrics, like temperature, thirst, and sex drive; and the brain stem, which is responsible for basic, biological functions like breathing, blinking and reflexes.

Without the ability to properly process leptin, their brains literally think that they’re starving. And the parts of the brain impacted are the primal ones with the most ability to trigger behaviors.

“Going on a diet under those conditions is tantamount to trying to hold your breath while running up ten flights of stairs,” says Dr. Thompson. “The part of the brain that’s active here is the brain stem. It’s simply not going to let you not eat. It thinks you're starving, and it’s going to go to great lengths to try and get you to eat.”

Dr. Thompson’s solution—and the way she managed to go from obese to a size four herself fourteen years ago—is detailed in Bright Line Eating. Her approach completely cuts out added sugars and flour, two of the main sources of high baseline insulin levels. As a result, leptin gets unblocked—sometimes in as little as a week, resulting in an end to ‘insatiable hunger’ and compulsive grazing. She’s helped people from more than 100 countries through the Bright Line Eating Boot Camp—an eight-week online program that can help you start training your brain for healthy eating habits.

By getting insulin back to a healthy baseline and re-introducing the brain to leptin, participants have been getting to goal weight and staying there long-term, something no other program has ever been able to prove it achieves. In fact, those who start the Bright Line Eating Boot Camp are 55 times more likely to reach goal weight within one year than those who spend that year in any other way. But Dr. Thompson says that Bright Line Eating gives people more than simply a slimmer physique.

“If you’re making promises to yourself [about your eating habits] that you’re unable to keep, you start to believe that you don’t care about yourself,” she says. “If you betray yourself all the time with food, you come to think that you don’t love yourself.”

Bright Line Eating gets your brain back on track, so you’re no longer stuck in the self-esteem-sapping cycle of endless trips to the fridge. In turn, people who abide by the program report greater feelings of serenity and peace around food, fewer cravings and freedom from insatiable hunger.

“Bright Line Eating helps make sure that you’re not battling your physiology,” says Dr. Thompson. “That’s why it works.”

Susan Peirce Thompson, Ph.D. is an Adjunct Associate Professor of Brain and Cognitive Sciences at the University of Rochester and author of the New York Times Best-Selling book, Bright Line Eating: The Science of Living Happy, Thin, and Free.

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