You Can't Optimize All Variables at Once
May 12, 2016
by William P. Meyers

Site Search

Popular pages:

Part I: Human Diet and Health

"You weed every year, and when you die the weeds grow over your grave."

Consider hunger as a variable. Generally we would consider it to be optimized when there is no hunger. For most of human history, health and a lack of hunger corresponded well. Hunger was the norm, and too much hunger meant disease and death. But now call health a variable. Optimize it. And you will find that, if you started with no hunger, and an overweight population, you end up with some hunger needed. Health optimization requires dieting, which requires hunger.

But health has many components to it, ranging from the ability to resist disease, to the ability to jog for an extended period of time, to measurements we are all now familiar with, like our blood cholesterol and glucose levels. We've been told our health depends on our genes, the bacteria in our guts, the food we eat, the toxins in air and water, and our emotional state.

As a general rule the variables, or moving parts, of a complex system do not all move in the same direction at once. Pushing any one variable to a desired level will push other variables in various ways. So you can't optimize all the variables of a system at once. This is particularly true in biology.

According the the Law of Evolution, each species is optimized for one thing: the survival of the species itself. Our current species sapiens has been around at least 100,000 years, our genus Homo has been around a couple of million of years, and our primate ancestors were around tens of millions of years ago. Our bacterial ancestors (which share a surprising amount of genetic code with us) have been around for a couple of billion years, most likely.

Conditions change. Even when conditions remain stable, species continue to evolve, partly to optimize against the stability, partly because of pressure from other species.

Hence dieting is a modern Tower of Babylon. It isn't just because of the food fad industry that profits from promoting pseudoscientific diets. These include high protein diets, high fat diets, diets with and without various forms of exercise, and all kinds of specific fads and taboos like promoting olive oil or quinoa, or eliminating wheat or even all carbohydrates. It is easy to find scientists and doctors who disagree about what foods we should eat. Some of the worst pseudoscience is promoted by doctors.

Despite the preoccupation with diet, the Coke and corn chips diet is still surprisingly common.

We seem to have more disease than our ancestors, but for the most part we don't. There is more childhood diabetes, which probably results from a lack of exercise combined with too many calories and in particular too much sugar. But on average people are living to remarkable ages. If you don't smoke cigarettes or have a drug or alcohol problem living to be 80 is not a big surprise anymore.

As far as I can tell, the only things worth optimizing in the typical human's diet (in nations where food is plentiful) is caloric intake and variety. Optimizing caloric intake is about keeping in a healthy weight range, which makes it easy to exercise and lowers the risk of diabetes and cardiovascular disease. Variety ensures that your body can pick and choose from a variety of nutrients, and fends off boredom.

This article is not about telling you what to eat or not eat. It is an introduction to the problem of optimizating complex systems. It is part of a series that will cover other health issues as well as personal finance, economics, politics, business, and culture.