PhotoAnyone who has ever gone on a diet knows how hard it is to stick to it so that you get results.

Part of the problem is breaking old habits, but for most of us, the hardest part is overcoming the hunger pangs caused by eating less of the food we like.

Hunger is an ancient product of human wiring. It ensures survival by telling the brain that the body needs more fuel to keep going. Hunger gets the brain's attention.

Unpleasant sensation

“One reason that dieting is so difficult is because of the unpleasant sensation arising from a persistent hunger drive,” said Bradford Lowell, a leader of a U.S. research team that is studying the brain's role in causing us to overeat.

The team has discovered that a brain circuit serves as the neural link that inhibits and controls eating, kind of like a switch. It found that this brain circuit not only promotes fullness in hungry mice but also alleviates the sensation of grating hunger.

“Our results show that the artificial activation of this particular brain circuit is pleasurable and can reduce feeding in mice, essentially resulting in the same outcome as dieting but without the chronic feeling of hunger,” Lowell said.

Now that this circuit has been identified, the researchers say they can develop a more effective diet drug.

Processed food

Stacey Cahn, an associate professor of psychology at Philadelphia College of Osteopathic Medicine, has also been studying why we get so hungry that we can't control our appetite. She's come up with a different answer.

Cahn says eating processed food makes it much harder to control your food cravings and that it's no accident. She points out food manufacturers have invested billions of dollars in making their products almost impossible to resist. It's just “good business” on their part, she says.

“Research shows that we’re much more likely to overeat processed foods than 'whole foods,'” Cahn said. “Snack foods that have an airy, crispy texture like cheese puffs leave us particularly prone to overeating because of vanishing caloric density. As the snack somewhat dissolves on our tongues, our bodies don’t register those fat calories, so we still feel hungry, and we keep eating.”

The smorgasbord effect

The reason a buffet is so hard on the waistline, she says, is because eating a single food item makes us feel full faster. But a buffet, with its wide variety of dishes, keeps us from habituating to any single one.

“That’s why processed foods like nacho chips are engineered to contain a complex spectrum of flavors,” she said. “So we keep eating. And while junk foods may lead to overeating, their unnatural ingredients may independently lead to weight gain.”

Cahn further claims that avoiding calories with artificially-sweetened beverages often has an opposite, unintended effect. Experiencing sweetness without the expected corresponding calories can cause hunger cues to be felt more intensely. The calories we avoid drinking a diet soda are more than made up when we give into temptation later on.


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