As we evolved, we created systems and behaviors to survive when droughts and poor eyesight made picking and hunting less than successful. We learned to thrive, and we learned to eat. In early times, our diets consisted of fruits, nuts, vegetables, tubers, and wild meat—foods that were, for the most part, low in calories. That’s not to say our ancestors didn’t enjoy their foods. They consumed their sugars through fruit, and they even splurged when they came across the Paleolithic Cinnabon—a honeycomb. The difference between their splurges and ours? They came across the sweet treats only rarely; it’s not as if they popped in for a 900-calorie sugar bomb every time they went shopping for a new buffalo hide. Add that to the fact that their definition of “searching for food” included walking, stalking, and chasing, not sliding the milk carton out of the way to find the pudding pack. It was a lot of work to get food, so they naturally burned many of the calories they consumed through the physical activity of hunting and gathering.

      The Heavyweight Fight: Genetics Versus Environment

      It’s easy to argue that lifestyle choices and lack of willpower are responsible for weight problems (it’s the argument that lean people tend to make). But it doesn’t explain the 95 percent failure rate after two years of people who have lost fifty pounds or more; they had plenty of willpower to lose but regained the weight nonetheless. Researchers argue that obesity is more genetically linked than any other trait except height-and at least 50 percent of obesity cases clearly have genetic components. Our take: The waist control game requires two players-environment and genetics. Even if your genes have made you predestined for a life of taking up two seats, that doesn’t mean you should abdicate control over your body. When you make the right behavioral and biological changes that we outline, you’ll be able to stay healthy and avoid the bad side effects of excess weight, like diabetes, high blood pressure (hypertension), and arterial inflammation. While 10 percent of the obese population has genetic challenges that may make a supermodel contract impossible, the bigger risk with these genes is not in the weight itself but in the predispositions for risks associated with obesity. For example, one genetic problem associated with being overweight is called leptin deficiency (leptin is a hormone associated with satiety, which we’ll discuss in the next chapter). Folks who either don’t produce leptin or block its signals usually become morbidly obese, and the problem is surely genetic.

      While some people have these abnormalities, they tend to be the minority of the population. If you need to worry about losing twenty-five, thirty-five, even fifty pounds, your problem is not likely to be genetic. Only when your excess weight exceeds one hundred pounds would most doctors consider testing for genetic abnormalities. Still, the example of leptin is only the tip of the scientific iceberg as far as genetics and obesity are concerned. As the fight against obesity continues, we’ll see more and more drug companies target genetic reasons for weight gain-that is, drugs that attack the genetic biochemical problems that may be contributing to your weight problem. That said, the onus of waist management still falls on you, to improve your environment and your behaviors so that your genetics can work for you, not against you.

      Because salt and sugar were scarce, our ancestors mostly feasted on grains, vegetables, and meats—for good reason. The meat provided the protein, vitamins, minerals, and fatty acids that helped them grow taller and develop larger brains, while the other foods gave them nutrients such as glucose, a simple sugar found in fruit and the complex carbohydrates of plants, that they needed to grow and develop, and for energy to move. And, of course, food was always fresh, as there was no canning or refrigeration to store up food for Super Bowl parties, or to sneak in an 11 p.m. bowl of sugar-coated oats.

      FACTOID

      The difference between obese people and thin people isn’t the number of fat cells, it’s the size of these cells. You don’t make more fat cells the fatter you get; you have the same number of fat cells you had as an adolescent. The only difference is that the fat globules within each cell increase as you store more fat. By the way, muscles work the same way: you don’t make more muscle cells; the muscle cells get larger.

      Another difference was that the meat our ancestors ate wasn’t like the meat we know today. Theirs was low in fat and high in protein; ours often comes in the form of corn-fed cows pumped up to make fattier, tastier cuts. Even today’s buffalo burger is corn-fed. Truly wild game has about 4 percent fat, while now most commercially available beef has nine times that amount. (The theory behind protein-heavy diets like Atkins is that protein reduces overall food intake and could reduce calories as well. The flaw is that eating proteins dripping in saturated fat, like bacon, isn’t exactly the same as eating the leaner, healthier forms of protein like chicken and fish.)

      The result: Your tribal forefathers and foremothers could eat anytime they could harvest or catch something, and still not put on excess weight.

      The lesson: Our ancestors never thought about a diet in the way we do—and their bodies had the approximate density of granite. Us? We obsess about diet more than red-carpet reporters obsess about designer dresses, and our bodies have the consistency of yogurt.

      Still, we can’t blame the advent of fast food and waffle cones for all of our weight issues. The downfall started in the pre-GA. (pre-Golden Arches) era—over 10,000 years or so ago, when agriculture first appeared. Agriculture allowed us to make more advances than a seventeen-year-old boy in a movie theater, but we paid a price for them. Besides Myth Buster sparing the lives of countless mammoths, the rise of agriculture ensured that we’d always have a steady supply of food—an advantage during times of famine, a disadvantage at the $6.99 Mama’s Kitchen Eat-Everything Buffet. With a constant source of food, people became less nomadic, and communities grew closer together. While the average life span increased (thanks to the elimination of the extreme sport of tiger chasing, with, perhaps, some help from sanitation and immunization), agriculture also brought its share of downsides: more bacterial infections, shorter stature, and rotting teeth that comes from eating refined sugar and less nutritious farm-raised food (overused soil depletes food of its nutrients). Our ancestors’ diets shifted from vegetables and meat to grains from the farms, essentially hindering them from getting the diverse mix of protein and micronutrients needed for brain development.