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!
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Posted By: Mark Sisson
I finally figured out why when I was young I was a super happy little barefoot outdoor kid all summer and a miserable, unhappy shod kid in school in the winter. Two reasons, I think: kids go inside for school, and I lived in Portland, Ore. and the sun disappears for months during the school year. No sun = no happy. I wonder if anyone has ever thought about seasonality aspects of education?
When I was a kid I used to love winter. I would run long distances and be outside a lot more doing more heavy and physical activities. One of my favourites was cutting the firewood every afternoon (and I was a scawny little girl). Now I get depressed in winter because I spend most of my time inside complaining about the cold and trying to keep warm in front of the fire. Stupid really.
Any advice for people who are allergic to nuts?
Yes. Don’t eat any.
More seriously, reduction in all allergins will help your tolerance to the occasional accidental exposure, because allergies tend to be threshold phenomena.
Seasonality is a huge issue for my family – we live in Northern Canada where the temperature can range from -40F in winter to 104F in summer. It’s snowing inches right now! We’ve been primal for about 3 months, but local fresh fruits and veggies are tough to get – most of our stuff comes from California. Not very sustainable. We’re currently researching edible plants that grow in our climate and urban environment and are delighted to discover there are lots of things that we can grow in our backyard. But since our growing season is only about 3 months long (zone 3) we have to learn healthy ways to preserve food as well. Freezing, and experimenting with lacto-fermentation is top on our list. On the up side we are surrounded by farming communities and clean grass-fed beef and pork. If we can be primal, anyone can! Of course, all suggestions to make it easier are welcome …
I just saw a BBC documentary called Crop to Shop on how damaging to the environment having e.g. potatoes year round in our supermarkets is. It is really frightening how we are damaging the planet for year round produce.
1. For the European market most potatoes are grown in the Egyptian desert where they use water from underground wells which have been there for millions of years and will never be replenished
2. The potatoes are kept moist for shipping by using peat imported 1,600 miles from Ireland and as peat takes so long to ‘grow’ it is also classed as a non-renewable source.
Check out ‘Crop to Shop’. Your jaw will drop!
Jason
It’s a huge issue. It’s easy for me to see when I walk into a grocery store here and see mangoes and fresh fish. It’s snowing here and we’re land-locked. If I have to choose though between seasonal local vegetables (squash and potatoes from last summer) and stuff from California, then we’re eating the stuff from California but we’re working hard to find a way to have less impact. It takes a tremendous amount of effort and research though, and it’s really tough to find the time. But it’s important to try, and easier than moving somewhere south. I think.
The book “Animal, Vegetable, Miracle” by Barbara Kingsolver is an interesting chronicle of one family’s efforts to eat only local food (mostly food that they grew themselves) for one year. When my husband and I lived in DC we had no problem eating a local diet save for a few things like lemons & fish. It was economical, too. We moved to Austin, TX a year ago and find it SO MUCH HARDER to eat a local diet here. There has been a bad drought that is just starting to turn around so local produce was very limited, poor quality, and expensive until recently. We have been trying to adapt but it’s been really difficult. I generally feel like eating in tune with the seasons where you live is the smartest thing from both health and environmental perspectives, and I am really looking forward to reading more of your analysis on the specifics of eating seasonally.
It definitely is all about where you live. Some places just might not be able to support humans. Funny Kingsolver starts her book out by fleeing New Mexico to find a place to live where food can be grown locally sustainably. As a DC guy myself I love the farmers markets we have but of course all that still needs to be trucked in from farms hours away.
Good Canadian Boy! I eat what is available…I don’t overthink things but I try to buy local as much as possible in season.
I have been pondering this topic and wonder if the whole seasonally eating thing is simply just that humans have evolved to not eat the same thing over and and over all the time.
No matter where Grok lived, he/she probably ate as much as possible of what ever was available and certainly not much was available all the time.
We do seem to naturally like variety in our food.
There are probably holes in this theory. Anybody?
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.
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.
At 125 years old I reckon you’ve got it cracked!
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..
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.
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.
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!
peace-
Awesome Brian, I couldn’t agree more. I say Shhhhh!, Listen. LOL.
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.
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.
‘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.
Heyy I like this, very comprehensive and love the facts that you are proposing
keep it up mark!