Philip J. Goscienski, M.D.
There were no scrawny Stone Agers, at least, not for long. Nature selected for the strong and vigorous and the rest became part of the food chain. There is plenty of fossil evidence to show that during the thousands of generations before the Ice Ages our forbears were tall, lean and muscular. Their existence was no meaner than that of modern primates living on the savannahs and in the forests of Africa, where food is relatively abundant. As the brains of modern-appearing Homo sapiens enlarged, so did their bodies. Skeletal remains dating back hundreds of thousands of years are thick-walled and heavy, especially where muscles were attached. Anatomists tell us that this indicates large muscles, much more massive than those of today's average human. Hardly surprising, since they needed muscle power for every activity.
A large mass of muscle has two advantages beyond obvious strength and speed. It is a storehouse for two nutrients, carbohydrate and protein. True famine was almost nonexistent during the Stone Age but periodic food scarcity was not. During periods of drought or extreme temperature variation there would always be some plants and animals that had evolved to survive under extreme conditions. Animals, including humans, that were able to accumulate reserves of fat, carbohydrate and protein were more likely to survive.
Plants store carbohydrate as starch. Potatoes, beets and carrots do it below ground; apples and bananas pack it into fruit; celery, rhubarb and sugarcane accumulate it in the stem. Animals store carbohydrate in the form of glycogen. Most of it accumulates in muscle, some in the liver and small amounts in various other organs. When we fail to eat carbohydrate for a day or two our bodies use up most of our glycogen stores to provide glucose, the primary fuel for every cell in the body. Small muscles can't store much glycogen and it is no wonder that most of us don't have much stamina. Without room to pack in that stored energy we run out if it quickly. Although we can derive energy from the breakdown of fat and protein, stored glycogen is our most important source of immediate energy.
Our muscles are composed primarily of protein, which is available as fuel when we deplete most of our glycogen and some of our fat stores. This explains why only about half the weight that we lose in a starvation diet, especially those that promote a very low carbohydrate intake, consists of fat. Lean body mass, mostly muscle but some from other organs, gives up protein to sustain life. Unfortunately, it is difficult to regain this muscle mass when starvation or dieting ends and normal food intake resumes. Repetitive dieting, especially with little or no exercise, always results in a gradual wasting of muscle and replacement by fat.
We require some protein intake every day in order to replace cells that turn over rapidly, including those that line the intestinal tract, repair damage and protect us from infectious agents. Hospitalized patients who receive only intravenous fluids, as following surgery for instance, give up body protein in order to heal organs and repair the operative site. The increased demand for protein may limit their ability to resist harmful — and increasingly antibiotic-resistant — germs in that environment. It's no wonder that thousands of persons die from infectious complications of surgery every year, and many others require a long convalescence.
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at firstname.lastname@example.org.