The reason I walk

This is a nice summation of the premise behind the Paleolithic diet.

“From the emergence of the genus Homo, over 2 million years ago (MYA), until the agricultural revolution of roughly 10000 years ago our ancestors were hunter-gatherers, so the adaptive pressures inherent in that environmental niche have exerted defining influence on human genetic makeup. The portion of our genome that determines basic anatomy and physiology has remained relatively unchanged over the past 40 000 years. Thus, the complex interrelationship between energy intake, energy expenditure and specific physical activity requirements for current humans remains very similar to that originally selected for Stone Age men and women who lived by gathering and hunting.”

[From the abstract : Cordain, L., Gotshall, R.W. and Eaton, S.B. Physical activity, energy expenditure and fitness: an evolutionary perspective. International Journal of Sports Medicine 1998; 19:328-335] [PDF to entire study]

Over the millennia, our crafty little monkey ways have lead to more and more inventions, techniques and access to resources which have made our lives “easier.” The authors of this article, renowned for their work in this field, do not go into the reasons that food became ever more abundant for us with little personal effort to produce it. However, it is my contention (and that of others) that the advent of cheap and easily transmuted fossil fuels have allowed us to achieve this state. My primary motivation for exploring these primitive ways, the ways we designed to live, is my lack of trust in the sustainability of this ‘way of life’; these fuels are running out.

But on the subject of walking, and Paleolithic exercise in general, the authors point out, “Overall, the Paleolithic rhythm involves days of fairly intense physical exertion which alternate with days of rest and light activity..” But how much physical exertion? In our modern world, “… physical activity for most people has become an extraordinary activity largely separate from other daily tasks and engaged in specifically to improve fitness variable such as endurance, strength and or flexibility.”

The activity per day guidelines recommended by the American College of Sports Medicine are, “participating in physical activity 3-5 days/week, at 50-85% maximum intensity, continuously for 20-60 minutes” along with “accumulating 30 minutes of physical activity over most days of the week…” However, when compared with the activity levels of the modern day hunter-gatherers, the Ache, !Kung, Agta, Hadza and Inuit, these guidelines fall far short, for their daily activity levels are much higher.

Evidence gained by observation of these modern hunter-gatherers, suggests that we were meant to walk as much as nine miles a day. Along with the fairly strenuous daily activities of the community. This is significant. For millions of years our closely related families of primates and even modern hunter-gatherers have had to walk a long way nearly every day to get something to eat. We are programmed to burn off far more calories each day then any of us in the west would ever dream of burning, even the athletes among us.

The difficulty with fitting this level of activity into our lives is not in retraining ourselves. In fact, what I have noticed is that one can quickly become conditioned to walking. After two weeks, eight miles does not strain me any more than three. What can become problematic is the amount of time it takes to do this. Three and a half hours of walking, the equivalent of ten miles at three miles an hour, is not a lot of time, unless you are committing yourself to doing it every day. Three and a half miles, six days a week, is 21 hours; that is a part time job. If it were not for my being marginally employed this summer, I do not know if I would have had the energy to do all this.

Nevertheless, I will continue at least until the new semester begins. The answer to regaining the balance may lie in increasing activity level in combination with intentional calorie reduction. Hmm, that sounds like most modern diet plans.