Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
25 Mar

The Question of Seasonality in Human Health and Nutrition

How important is seasonality in our understanding of human health? In last week’s nuts post, I referred to the seasonality and intermittence of nut availability in the wild, implying that because they weren’t available to our ancestors on a year-round basis, excessive daily nut consumption may not be in our best interest. Regular, consistent, high-volume nut ingestion may not make sense in the light of human evolution, but does that necessarily make eating nuts – or, really, any food – in anthropologically unrealistic amounts detrimental to our health?

What about seasonal behavioral patterns, or seasonality of access to sunlight? Does it make sense to view our every move, our every tradition, in the light of the seasons? What do we mean by “seasons,” anyway – aren’t the seasons different depending on several factors, like proximity to the equator? Or is there an ideal seasonal cycle all humans should strive to follow, regardless of location or background?

To establish whether or not an ideal human seasonality even exists, it would help to establish what we know about our earliest stomping grounds. What was the climate like where and when we evolved? What were the seasons like? Humans evolved in East Africa, with modern Homo sapiens first appearing around 200-250 thousand years ago. It’s popular to suggest we evolved in a stable, constant Edenic landscape: lush forests, grasslands teeming with wild game and edible vegetation, steady rainfall, predictable seasons. The reality wasn’t so neat and smooth though (is it ever?). In fact, the region has seen major topographical and climate changes over the ages, beginning with the clash of the Indian and Asian tectonic plates 40 million years ago, which set into motion both the uplift of the Tibetan plateau and massive volcanic activity in East Africa. The growing Tibetan plateau deflected moist air away from East Africa, while the volcanic activity coincided with rifting in Ethiopia. The newly formed rift valley and accompanying rift shoulders, or mountain ranges, led to even more deflection of moist air, and what began as a uniformly flat plain covered in rainforest became a landscape of plateaus, mountains, and valleys featuring both cloud forests and desert scrubs.

Temperature was fairly constant, tending toward the warmer side of things, but the seasons were characterized by intense bouts of rain and drought. A wet period might last thousands of years, only to be followed by centuries of brutal drought. Enormous lakes could dry up in a hundred years (a blink of an eye), rapidly changing an established people’s way of life and spurring innovation. Seasonal cycles no doubt followed the wet/dry dynamic, and this is where and how we evolved – in a constant (on the large scale) state of flux. It was a tumultuous, highly variant environment, and some anthropologists think it had the effect of producing the most adaptable species on the planet: us. Good thing, too, because if we were going to successfully migrate to every corner of the globe, we had to be prepared to make quick adaptations.

Based on that ability to adapt, I lean toward the absence of a cut-and-dry seasonal mentality that applies to all humans. I mean, just look around. We see and hear examples of humans surviving, even thriving, in any locale, under any climate, and exposed to any environmental pressure. We live where it rains 3/4 of the year, and we live in bone-dry, arid deserts.

Before I sat down to write this, I was planning a fairly basic examination of seasonal foods. Once I began digging around, things became a little more complicated (as they always do). I think I’d be shortchanging the topic and over simplifying a complex issue if I stuck with what I imagined the script to look like. It’s not so much that there isn’t a single seasonality that we can all adhere to; it’s that there are multiple cycles that “work” with our respective physiologies. That’s the whole point of being human, really! We adapt, we conform, and we mold.

I have a feeling this will be a broad topic, and I won’t be able to cover everything, but I’ll try in a series of upcoming articles: The relationship between Vitamin D and fructose consumption, spring and winter fats, egg, meat, and tuber availability, intermittent fasting, the remarkable similarities between the climate of the modern Hiwi tribe of Venezuela and that of our early human ancestors in East Africa (found the free full text of a fascinating study) and what they all indicate about our ancestral seasonal diet.

In the meantime, leave me your thoughts in the comments section, and stay tuned!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. There are probably holes in this theory. Anybody?

    Sharon wrote on March 27th, 2010
    • well i think he ate a lot of meat and fish year round and that was the bulk of the calories–a constant. then the rest did vary. he was scrappin. maybe more lazy days in summer picking berries–and in winter, hunker in the cave around the fire with a really BIG kill. some roots and and mushrooms in fall and spring. native americans made meal out of acorns, of course, and stored it.

      DThalman wrote on March 28th, 2010
  2. Grok was an opportunist….when he found food he ate it! :-)

    I live in MN also – originally from Philly, spent 115 years in NC, and 10 in Chicago.

    I like a change of seasons, but the extreme cold and inactivity in the winter get to me… I gain back the same 15-20 lbs every year… my work schedule/commute limit my choices as far as workouts. Ideally, we would like to move to the Rockies and try our hands at a relatively self-sustaining lifestyle.

    This is an interesting topic, because I have a hard time differentiating between feeling compelled to stuff my face with crap from Oct/Nov until March – or is it emotional habitual eating of comfort food… fall foods, Thanksgiving Christmas, comfort food…

    it all goes back to the nature vs. nurture debate… and maybe it is really a little of both.

    fit4lifegal wrote on March 27th, 2010
  3. At 125 years old I reckon you’ve got it cracked! :-)

    Kelda wrote on March 27th, 2010
  4. As with CULTURE, humans moved long ago to all parts of the Earth, often times in unfit environments for optimal human health…

    We are NOT meant to live on cold climates… hance, warm and tropical climates are our basin of origin..

    lee wrote on March 27th, 2010
  5. I’ve noticed for many mahy years of tracking my health/fitness, that EVERY winter, regardless of how careful I am, I ALWAYS gain weight. At this point, I’m thinking that it is in my DNA…that when my body senses the colder, darker climate it automatically goes into some type of preservation mode. Just a theory, but that’s where my head is at this point…I can come up with no better explanation.

    Bob Mass wrote on March 28th, 2010
  6. It’s kind of Mark to take a stroll up this side street, especially since he lives in Southern Cali. I live in Southern Oregon and by this time of year, I need SUN…got back from Palm Springs this morning…the spring break dose of sunshine always helps see me through. I think our bodies are attuned to the seasons–I sleep more for sure when the days are shorter. Mood differences, too.

    DThalman wrote on March 28th, 2010
  7. Another great reason to
    listen to our bodies as
    opposed to being ideological
    about what is ‘healthy’.
    We already have the answers,
    we simply have to be willing
    to ask the question and
    take the appropriate action!


    Brian wrote on March 29th, 2010
  8. Awesome Brian, I couldn’t agree more. I say Shhhhh!, Listen. LOL.

    Allison wrote on March 29th, 2010
  9. I just moved back to Los Angeles, closer to sun and beach ( I live only 10 miles away from it) I lived in chicago for 2 years. it was a drag. Can not emphasize the point how much great weather adds to over all well being and mood, when its sunny out, sky is blue, its warm – makes it pleasant to live.
    Important thing however not to take it for granted. Which I noticed lots of people do. They live in southern california, and yet they never go to the beach or nature. they get wrapped up in their problems so they choose to stay inside, watch tv, drink and smoke in the bars and don’t reconnect with the planet or even get enough sun.
    I go to beach regularly. Just to sit there or walk around and after I do I always feel relief, energy and calm in my mind, as if I took some magic pill :-)
    On the other hand like mr. Jim Rohn used to say: if you don’t like where you live -move. you are not a tree.
    So I see these people sit and complain they don’t like weather, they dont like where they live and yet they stay there for 10-20-30 years and whine about it. because they own stuff. Or should I say stuff owns them and they find themselves not being able to leave. ( too expensive to move, to big of a deal, too this too that).
    Get into action. Do what you want to do. It will give you more confidence, it will make you feel so much better in the long run. you gonna thank yourself for it.

    Ed - Computer Repair Los Angeles wrote on March 31st, 2010
  10. I think the most important thing about seasonality is eating what foods are in season. This is mainly due to the fact that they are fresh and full of nutrition. If you eat food that is out of season, it has obviously travelled a long way, probably from some questionable origin, and may not be all that healthy or nutritious. Now that I am primal I am trying to stick to eating what is in season in my local area.

    Angelina wrote on March 31st, 2010
  11. ‘there are multiple cycles that “work” with our respective physiologies’

    I agree with this, but I would think that there is an ideal that will give us optimal health. While we may be able to change our habits in order to reach optimal, or just say “good enough”, it would be nice to know where optimal lies.

    Dennis wrote on April 13th, 2010
  12. Heyy I like this, very comprehensive and love the facts that you are proposing :) keep it up mark!

    Rueban wrote on May 4th, 2010

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