This year we’re focusing on energy—which of course comes from eating food. But overeating—eating more than we need to meet biological demand—can weigh us down, literally, with energy stored as fat.Our nation is obsessed with food and weight. We love to eat, eat a lot of the wrong things, and eat more than we need, so we’re constantly looking for ways to lose weight. Food psychologist Marc David reports that nearly 50% of little girls in the U.S. ages 3-6(!) are already concerned about their weight and report that they are on a diet, while about 1/3 of American adults are on a diet at any given time.Did nature make a mistake in giving us an appetite that drives us to overeat?Dr. Doug Lisle, PhD, co-author of The Pleasure Trap, has an answer for this. Our primitive ancestors and their appetites were perfectly adapted to their environment. Three instincts gave them an evolutionary advantage: 1) the drive to experience pleasure; 2) the drive to avoid pain; and 3) the drive to be efficien…