Say good-bye to lean cuisine. If your goal is successful dieting, you'll do better with what might be called keen cuisine.
Sophisticated psychological processes like willpower and negotiation—even lending a helping hand to others—may embody your character but they are also fed literally by glucose that circulates from gut to brain. Exercising the self-control needed for dieting, overriding urges, paying attention, or engaging in any effortful executive brain function imposes unusual nutritional demands on the brain. That makes a strong and steady supply of the mind's preferred energy source a nutritional requirement.
"Eating foods that provide stable and healthy glucose levels should help people muster their self-control," says Matthew Gailliot, professor of psychology at the University of Amsterdam. "It is sadly ironic that people might fail at dieting so often because dieting reduces the very energy source—glucose—needed to diet."
Which meals provide optimal energy for such uniquely human mental activities? "Focus on foods rich in lean protein and complex carbohydrates," says nutritionist Jeannie Gazzaniga Moloo of Sacramento, California. Such foods are metabolized at a steady rate and lead to stable blood-sugar levels. Think low-fat yogurt and fresh strawberries. Veggies with a hummus dip. Fish or grilled chicken.
In addition to the right foods, timing is everything in keen cuisine. "Eat every three to four hours and make sure the food choices are rich in complex carbs and lean protein to sustain glucose levels," says Moloo. And if you know you're facing a stressful situation, having a healthy snack beforehand—peanut butter on whole-grain crackers, say—could help your blood sugar rise to the occasion.
Otherwise, decision-making and effortful control of thoughts are impaired. The brain's supply of glucose gets quickly depleted by acts of self-control. Overriding automatic response tendencies consumes significant amounts of real energy.
"Willpower is more than a metaphor," says psychologist Roy Baumeister of Florida State University, who explained the starring role of glucose in psychological high-wire acts in an issue of the Journal of Personality and Social Psychology: "The human body is undeniably an energy system. Evolution gave us this new and more complicated way of acting, but it's expensive in terms of fuel burned. Being our better selves is biologically costly." We pay a price for the uniquely human ideals of virtue and wisdom: Meeting them consumes more energy than ordinary cognitive processes do.