Diets and the Unfairness of Evolution---Maybe
It's spring, temperatures are going up, and winter-shielded flesh is coming out of hiding. Often enough, you find there's a bit too much of it. Only optimists think baseball is America's warm-weather pastime. Actually, it's dieting.
Dieters nowadays are barraged with so much information regarding the number of things hazardous to human health (including too-stringent dieting) that a friend of mine claims the thing to do is buy a box of cake mix, throw away the contents, and eat the box. Steamed, of course. Add no salt. It's free of fat and cholesterol, high in fiber-surely perfect health food. I warned her that the dyes used to color the box are probably deadly. Even plain brown wrappers usually are laden with residues of evil chemicals. It seems we just can't win.
As dieters, doctors, and parents of small children have long complained, food that is good for you just doesn't have the appeal of food that isn't. Worse, perfectly healthy food gains in appeal when we deck it with unhealthy additions. Think of the noble baked potato; think of how we usually eat it. The most self-controlled among us add salt, while the more indulgent ladle on butter, sour cream, bacon bits, gravy...Then there's the near-perfect strawberry, which we greatly prefer to eat well sugared, sandwiched in a cake made with lots of fat and garnished with masses of whipped cream. Why should we do this to ourselves? What makes us find salty, sweet, and richly fatty things so delicious?
I confess; the truth is, nobody really knows. But I have a theory, developed during the long minutes it takes me to pass the ice cream and frozen pies section of the supermarket on my way to the apples and grapefruit. I blame it on evolution.
Think back to our long-distant ancestors, omnivorous little folks scrabbling hard to make a living. It wasn't easy. We didn't have the fangs, claws, or speed necessary to make good predators; we didn't have the robust and complicated digestive systems necessary for successful browsing or grazing, so we couldn't live on grasses and shrubs. We were pretty well stuck with fruits and shoots, seeds and tubers. Low-calorie, low-salt, low-sugar, high-fiber diets were inescapable--and marginal for survival.
Eggs would have come as welcome (and relatively rare) additions; fatty red meat would have been a wonderful high-energy and high-protein boon. Humankind, or proto-humankind, evolved for what we now think of as a healthy diet, but the craving for the so-called unhealthy foods would have evolved right along with it. Sodium isn't that common in nature, and getting enough of it would be a challenge. Quite probably we are all descended from creatures with a sensory system that sent up a "Good stuff!" signal at a salt lick.
Similarly, sweet tastes usually accompany a fairly high calorie content, and fatty things always do. People who are trooping all over the plains of Africa with nary a store in sight don't need to worry about dieting; they need to pack in the highest calorie count for the least expenditure of energy that they can. So, while all our systems were adjusting over millennia to the diet that nutritionists now urge upon us, our brains and senses were simultaneously building in the cravings for foods to make living easy.
I think this is a sensible theory, although it doesn't make passing the pie display any easier. If I'm right, all we pudgy people can do is acknowledge the strong voice of our ancestors' wisdom, and remind them firmly that times have changed.
