Intermittent Fasting – Ancient or All the Rage?

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Prepared by: Jenn Camirand, BA, R.H.N., CNE 

It is within our biological nature to accept current circumstance, adjust necessary behaviours, and then, adapt to environment, be it internal or external.  Our ability to adapt is directly, if not intrinsically, linked to our humanity, to the very genetics that keep us alive, and safe from extinction.

Homeostasis is the balancing of pre-set internal controls, with alarms set to sound at very specific limits. As one alarm is turned ‘off’ another will be turned ‘on’. When satiety has been achieved, eating is turned off, and when eating is turned off, fasting is turned on.  Within one homeostatic mechanism there will exist another. And so, it happens that whilst eating, insulin levels will rise and then begin to drop whilst fasting, and continue to drop for up to 24 hours, before another homeostatic mechanism may sound a different alarm, and so the story goes, again and again.

It is not enough that these marvellous mechanisms are able to maintain an overall state of equilibrium within the human body. It must also be acknowledged that in their response to change they are constantly generating new responses that will, themselves, lead to adjusted behaviours, and over time to adaptation in the form of change. This change is evolution.

Would we have evolved with such a profound ability for balance, and requisite for homeostasis, if it were not absolutely necessary for our very survival, both short and long term? Would each physiological homeostatic mechanism come equipped with safeguards, built-in buffers, and even in some cases abilities, to not only adapt, but to perform better under unfavourable circumstances than favourable?

History, and with it evolution, has been kind to us, if, that is, we heed the lessons that can be learned from the experiences of our ancestors, historic and pre-historic. There may be no greater case in point than that of Intermittent Fasting.

If we take a moment to think back, as far back as our limited modern-day imaginations can conceive, we might close our eyes and find ourselves dropped into a model of eating that is over thousands, possibly even millions of years old. We would concede to a world absent of towering office buildings, supermarkets, and fast food 24-hour drive-throughs, and we might just find ourselves huddled into a tightly-knit small collective. Maybe under a tree, or in a cold damp cave, clinging only to the necessary items needed to get us through each day in order to avoid succumbing to the dangers and ravages of a world in which those who survived did so by hunting and fishing, sometimes foraging and maybe even, from time to time, scavenging. One thing is undeniable, they were Intermittent Fasting, waiting, living, maybe even thriving, days, weeks, and possibly even months without a consistent food supply. And yet, logic, and history will clearly tell us that it is those who suffered the greatest that lived to tell the tale.

Could it be true? Could it be that longevity and a salubrious life are the result of a minimalist existence, more specifically, a restrained way of feeding?  This is not to say that I am in favour of having to rely exclusively on hunting or fishing for my daily meal, nor do I want to give up my evenings out dining with friends in lieu of staying home to manufacture my own blankets and weapons. But maybe, just maybe, doing less in this very case could, in the long run, result in an outcome of more.

Is it possible that by making key changes to my daily dietary regimen and learning to better understand how my ancestors were able to not only survive, but thrive, in times of limited food supply may actually contribute to better physical and cognitive health? Could getting our foot off the food accelerator and onto the brake, actually save our species from self-destruction?

These are only some of the questions that come to light when one, if charged with the task of unravelling the intricacies of Intermittent Fasting, may very well find themselves asking. And for some of them, I may be able to provide some straightforward but not necessarily easy answers, in the context of this brief article.

Let’s be clear on one thing.  Fasting is not starvation. While it is more than likely true that many of our ancestral cave-crouching relatives did die from starvation, as starvation by definition means to suffer or die due to lack of food, fasting on the other hand, specifically Intermittent Fasting, simply means that feeding occurs at irregular rather than regular intervals, not uninterrupted or constant. Is the implication then, that WHEN we eat, and how often we eat, may actually be more important than what we eat? Bluntly? Yes.

Those who survived, adapted.  The suggestion is that, as a result, we are better adapted to scarcity than abundance.  And yet, we practice abundance. These adaptations can and do translate in our modern-day physiology, with weight loss not the primary benefit, although for some it may be a significant side effect.

Proponents believe that the primary reason to practice Intermittent Fasting is to lower insulin levels. If insulin levels, very low insulin levels, are maintained for a longer than usual period, the following benefits may be achieved. Changes in hormonal function, loss of adipose tissue, lowered risk for type 2 diabetes, reduced oxidative stress and inflammation, improved heart health, cellular repair known as autophagy, improved brain health, lowered risk for Alzheimer’s, Parkinson’s and Huntington’s diseases, and resultantly an extended lifespan. There is some science to support the practice of Intermittent Fasting and I have listed some interesting reading below.

Modern day Intermittent Fasting can be practiced in many forms, from limiting food choices, shortened eating windows, skipping random meals, alternate day fasting or even eating minimal calories one day and then consuming a regular caloric intake on another.  Whatever method of Intermittent Fasting you choose, it is of utmost importance that it suits you and your lifestyle, and that it is achievable and enjoyable.

If you are new to fasting I suggest that you begin with a whole foods diet, ensure that you are getting plenty of clean water, good rest, and at least moderate daily movement. When these things are in place you can begin by pushing your first meal of the day back by one hour in the morning, and your last meal of the day forward by one hour. If after one week you feel you have adapted to this method of eating, you may want to look further into the practice of Intermittent Fasting and a method that works best for you.

Last, but not of least importance, if you are like many North Americans and suspect that you may have underlying blood sugar issues, or have been diagnosed with an illness, it is recommended that you consult your primary care practitioner for guidance as to whether Intermittent Fasting is a lifestyle change that you might embrace.

For further information on how to proceed with an Intermittent Fasting program of your own you can contact

-Posted February 2019-


Catenacci, V. A., Zhaoxing, P., Ostendorf, D., Brannon, S., Gozansky, W. S., Mattson, M. P., . . . Donahoo, W. T. (2016). A randomized pilot study comparing zero-calorie alternate-day fasting to daily caloric restriction in adults with obesity. Obesity.

Freese, J., Klement, R. J., Ruiz-Nunez, B., Schwarz, S., & Lotzerich, H. (2018). The Sedentary (r)evolution: Have we lost our metabolic flexibility? F1000Research.

Gabel, K., Hoddy, K. K., Haggerty, N., Song, J., Kroeger, C. M., Trepanowski, J. F., . . . Varady, K. A. (2018). Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutrition and Healthy Aging.

Kahleova, H., Belinova, L., Malinska, H., Oliyarnyk, O., Trnovska, J., Skop, V., . . . Pelikanova, T. (2014). Eating two larger meals a day (breakfast and lunch) is more effective than six smaller meals in a reduced-energy regimen for patients with type 2 diabetes: a randomised crossover study. Diabetologia – Journal of the European Association for the Study of Diabetes (EASD).

Klein, S. O., Holland, B., & Wolfe, R. R. (1990). Importance of blood glucose concentration in regulating lipolysis during fasting in humans. American Physiology Society.

Longo, V. D., & Mattson, M. P. (2014). Fasting: Molecular Mechanisms and Clinical Applications. Cell Metabolism.

Longo, V. D., & Panda, S. (2016). Fasting, circadian rhythms, and time restricted feeding in healthy lifespan. Cell Metabolism.

Mattson, M. P. (2014). CHALLENGING ONESELF INTERMITTENTLY TO IMPROVE HEALTH. Dose-Response (Formerly Nonlinearity in Biology, Toxicology, and Medicine.

Mattson, M. P., & Wan, R. (2005). Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. Journal of Nutritional Biochemisty.

Nair, P. M., & Pranav, K. (2016). Role of therapeutic fasting in women’s health: An overview. Journal of Mid-Life Health.

Patterson, R. E., & Sears, D. D. (2017). Metabolic Effects of Intermittent Fasting. Annual Review of Nutrition.

Patterson, R. E., Laughlin, G. A., Sears, D. D., LaCroix, A. Z., Marinac, C. B., Gallo, L. C., . . . Villasenor, A. P. (2015). Intermittent Fasting And Human Metabolic Health. Journal of the Academy of Nutrition and Dietetics.

Sutton, E. F., Beyl, R., Early, K. S., Cefalu, W. T., Ravussin, E., & Peterson, C. M. (2018). Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metabolism.

Varady, K. A. (2011). Intermittent vesus daily calorie restriction: which diet regimen is more effective for weight loss? Obesity Reviews – International Association for the Study of Obesity.

Vasilescu , M., & Rosulescu, E. (2017). Is Intermittent fasting a scientifically-based dietary method? Medicina Sportiva.

A member of faculty with the Canadian School of Natural Nutrition (CSNN) since 2012, Jenn  holds a Bachelor’s Degree from the University of Waterloo, received her Nutritional training at CSNN, graduating class valedictorian in 2007, was awarded a Certificate with Honours from the Academy of Culinary Nutrition in January of 2015, and is a Member of the Institute for Functional Medicine. Most recently, she has been awarded designation as a Nutritional Therapist within the United Kingdom.

Jenn stands firm in the belief that we are more than just the sum of our parts, and that our current state of health and nutritional status is the manifestation of all of our experiences, not just the foods we eat. When we are able to truly focus on our own health through education, and an understanding of who we are, great change can take place. This belief, along with a passion for Physiology and Epigenetics, Functional Medicine, and Anthropology, are all brought forth to the classroom, her nutritional practice, her writing, and research.

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