Occasional Fasting

Occasional Fasting | The Paleo Diet


You may have covered this issue already, I have not read that much of your work.

I thought I would point out though that Paleo humans likely went through periods of enforced occasional fasting due to a lack of game or a temporary lack of success in hunting. In fact, there were likely alternating cycles of gorging and fasting. This alternating cycle would change the data on the Paleo diet as modern humans are not likely to be undergoing the fasting phase.

It seems like doing a study using the climate record might help as Paleo man may not have migrated as much as the animals that they hunted.

Have you already covered this?

Just another nutrition student,


Maelán Fontes’ Response:

Dear Bob,

We agree in that hunter-gatherers would probably have been forced to observe periods of intermittent fasting.

In our archive you can find a published issue of our newsletter (Vol. 1; Issue 3) where Dr. Cordain reports that hunter-gatherers usually ate a single meal in the evening and probably breakfast using leftovers from the night before. This makes sense as they spent the day engaged in foraging and hunting activities and returned to their camps in the sunset. Some of the beneficial effects of intermittent fasting are likely due to caloric restriction, a well as known interventions that increase health in animals and humans, and lifespan in animals such as hamsters, mice, rats, fish, insects and worms.

A feast-famine, exercise-rest cycle has been postulated as a healthful lifestyle similar to that of human beings in the paleolithic. Famine and exercise (simultaneously) decrease muscle glycogen and triglycerides stores increasing AMPK and GLUT4 expression. These two proteins are involved in glucose and triglycerides homeostasis, leading to an efficient storage of energy and increased physical performance. If hunting is successful, a replenishment of glycogen and triglycerides is produced. This is followed by a relative period of rest. This efficient storage of energy increases the probabilities of surviving during another famine/exercise period.1

This should be a healthy way to improve health and physical performance from an evolutionary perspective.

1. Chakravarthy, M. V., Booth, F. W. Eating, exercise, and “thrifty” genotypes: connecting the dots toward an evolutionary understanding of modern chronic diseases. J Appl Physiol, 96 (1); 3-10.

I hope this helps.

Maelán Fontes MS Ph.D. candidate in Medical Sciences at Lund University, Sweden

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About the Author:

Loren Cordain, PhD, Professor Emeritus Dr. Loren Cordain is Professor Emeritus of the Department of Health and Exercise Science at Colorado State University in Fort Collins, Colorado. His research emphasis over the past 20 years has focused upon the evolutionary and anthropological basis for diet, health and well being in modern humans. Dr. Cordain’s scientific publications have examined the nutritional characteristics of worldwide hunter-gatherer diets as well as the nutrient composition of wild plant and animal foods consumed by foraging humans. He is the world’s leading expert on Paleolithic diets and has lectured extensively on the Paleolithic nutrition worldwide. Dr. Cordain is the author of six popular bestselling books including The Real Paleo Diet Cookbook, The Paleo Diet, The Paleo Answer, and The Paleo Diet Cookbook, summarizing his research findings.

1 Comment on "Occasional Fasting"

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  1. SportsGuy says:

    I think perhaps this reply is a bit off. If you read Mattson’s work on IF, it seems more accurate to say that at least some of CR’s benefits are due to IF, not the other way around.

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