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
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I live in Minnesota and the weather sucks most of the year!
I’ve thought about this before in context of how we slim down in the summer for swimsuit season but yet summer for animals, like bears, is when they fatten up to be ready to survive the upcoming winter.
Yeah, the weather does suck. Another Minnesotan right here!
One more year of college and I’m moving to Hawaii, though.
I’m hoping to move soon to someplace warmer. Done with MN ‘ice and nice’.
I live in Michigan and have done so my entire life (22 years). I hated it for 21 years and then decided to somewhat enjoy it. I was able to but am excited to say that I will be moving out of Michigan to somewhere with weather that allows me to golf year round
Wait, I love the weather in the upper midwest!
I wanna live where it’s 75 and sunny all year long. Anyone know where that is?
Southern California – that’s the place you want to be. Been here for 25 years after getting out of Texas ( Love Texas, to visit only)
SoCal is really nice but lets be real, you can’t beat Texas and you for sure can’t beat Texas women. I’ve lived in New York, Los Angeles and in Texas and no place can touch Texas women.
Looking forward to this series of articles, the whole topic is really fascinating.
Thanks for yesterday’s webcast, it was great to see you in the ‘flesh’ LOL! Although I have to say I’ve struggled through today with 3 hours missing sleep from the middle of my night, but it was worth it!
I was born and raised in Ohio — the Cleveland area — and grad school brought me to Texas. I love the abundance of sunshine, but I HATE winters here! 34 and cloudy and raining. Absolutely miserable. If it has to be cold and gray, it better be cold and gray and snowing, in my opinion, so I can go outside and build snowmen or go skiing or ice skating.
Having said that, I should be moving in the near future, and when it came down to choosing between Chicago and Virginia Beach, weather definitely played a role and the hubby and I agreed on Virginia Beach.
Of course, it doesn’t snow in Chicago in winter, either, it’s just bitterly cold and windy…
Native Texan here – we don’t want no snow.
Anywhere except the Northern Panhandle in TX shuts down for snow.
Snow’s twice as nice as rice,
and a treat as neat as wheat!
agreed! Keep that nasty snow in ohio we don’t want it in Texas!!
It snowed way more than I can handle in Austin this winter!
You must have missed the last couple of winters in Chicago. We’ve had over 50″ of snow each of the last three years. Our average snowfall the last 10 years is only about 38″ but things have picked up as of late. We just didn’t get it all at once like the east coast. But yes, there’s still been plenty of wind and cold
Just for the record, I’m not sure where you are, but in N. Tx we’ve had the 2nd snowiest winter on record – 17.6 inches!! Yeah, that may not seem like much to you guys up north, but it’s been ALOT for us. Heck, when we got 8 inches last week, the kids weren’t even building snowmen – they were bored with it! Fortunately, it was gone in less than 24 hrs.
I think that by August when it gets to 110 degrees that we’ll ALL be wishing it was closer to 34 – with or without snow!
Texas Gulf coaster here. Snow more than once and multiple days of freezing weather this year devastated my Plumeria. We don’t want no snow here on the coast either!
thanks for this topic! i finished lights out, a great read and all about this but in a huge amount of detail. highly recommended book that goes nicely with mark’s book.
I’m really glad you’re covering this; it’s something I’ve been thinking about for a while now. I wonder aloud when I see all the fresh, tropical fruits in the supermarkets in mid-winter on one hand, and our seasonal local farmer’s market that shuts down half the year, and is otherwise ruled by apples and tomatoes.
I’m also a complete coconut addict, and I live no where near where they grow now.
(Not that it slows me down much, but it does make me wonder!)
p.s. I’m making my way through The Primal Blueprint now, and I have to tell you how impressed I am. I figured a lot of it would be a re-hash, since I read the blog everyday, but it’s fantastic. I’m blown away by how much I’m getting from it. Thanks again.
I have often wondered if the flu and cold season have more to do with depressed immune systems during the winter than anything else. Maybe due to less sunlight and less D, maybe due to the produce available. (Don’t you also want to get more D than A?)
If so maybe that would be an argument to get more out-of-season fruits and vegetables from the southern hemisphere during the winter up here.
And then if we do eat out of season what is the best way? In the winter is frozen best since it’s frozen when ripe and shipped, rather than “fresh” which was picked weeks before it’s ripe? Does it make a difference health-wise? Same for canned like canned tomatoes which every good southern Italian here uses in the winter
It’s a subject I’ve been interested in learning glad you are taking it up.
based on stuff I’ve read i think there is something to that–impaired immune, lack of sun, vit D.
Mark –
Echoing the comments of other readers, I’m really glad you are covering this. I’m interested in the tension between being primal vs being sustainable. As someone who lives in the Northeast United States, if I were trying to eat only local, organic and sustainable food while also staying true to primal diet (i.e. avoiding tubers) getting through the winter would be a challenge – as I imagine it was for American Indians and early European settlers. Well, not AS difficult, but you get what I’m saying.
Looking forward to further posts on this topic.
I definitely eat a TON more local fruit in the summer. The winters I really only eat some frozen berries from the previous summer(s), or some stored apples from the fall harvest. Other than that, I don’t vary my diet much between seasons. I intermittently fast year round, and always keep it low carb (and 95% grain free…lil’ bit of rice here and there…and the occasional treat).
That being said, I’ve always thought it was weird that I can get a ripe juicy pineapple in January in Ottawa, Ontario Canada for 4$! That must weird some bodies out…in the summer, I bet not so much.
Most of us carry our ancient tropical climate wrapped around us like a shroud. We hike our heat up to 70 F or higher, we wear layers of warm clothing in winter. Does pretending our skin exist in the tropics change our dietary and lifestyle needs? Should we acclimate more to our own climate?
I’m not sure how humans handled the frigid cold of my mountain home eons ago, but I bet they didn’t wear as many layers as I, bet they didn’t keep a humidifier going all winter long.
something interesting found brought to my attention by timothy in the forums. a fourth kind of hominid has been found in siberia. it is thought to have left africa 500,000 years before the neanderthals did. they survived in that harsh cold weather until around 40,000 years ago. still much is unknown tho but do a search on it, it is very interesting!! (at least anyways it captures my interest heh)
Exactly – we recreate the tropics in each of our homes – indoor heating. We try to replicate a warmer environment as much as possible. If we were to truly go seasonal we’d have to give up fresh fruits and veg – do you think our ancestors would have passed up a fresh bit of greens in the winter if they could have had access?? I somehow doubt it.
Then there’s the whole Neanderthal admixture in most of the northern members of our species. I can’t simply say that “we” evolved anywhere for any climate. Each person has to find and adapt to their actual environment and ancestry.
But I think we all know that already…
There was no “Neanderthal admixture” in any members of our species, northern or not. The DNA sequencing, now complete, verifies that there was no “admixture”. If you have a credible (scientific…not some racists clap-trap) source saying otherwise, you should cite to it. Otherwise, you’re passing off nonsense as information.
Yeah, maybe I’m two or three years behind the news here, but thanks for going straight to the charge of racism. Very effective way of shutting down a conversation.
Science doesn’t need insults to be right.
Well, sorry where sorry is due. Generally, where I see a viking avatar and hear the neanderthal/European/Viking/redhead/etc. theory, it’s pretty straight up racism and the next thing you know someone’s trying to tell you that stormfront has the answers. I didn’t mean to charge you with racism, though, (or, more accurately, “racists clap-trap”) I was actually angry at the racist clap-trap that people will sometimes link. Not you. Sorry about that.
Bit “snippy” aren’t we Jack??? Saw no malice or racism at all in Baerdric’s comment. And, whilst I’m not doubting your info, where’s your scientific citations? You know, since you’re demanding it of others.
Yes, we were a bit “snippy”. I was justifiably snippy, but not justifiably at Baerdric, as it turns out, and I’ve apologized accordingly now, SO GET OFF MY BACK ABOUT IT!
No, seriously, my snippiness was accidentally (gramatically) mis-directed toward Baerdric.
The results of the Neandertal Genome Project have been questioned. Or has the KKK infiltrated the Institute for Human Genetics at UCSF?
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014787/?tool=pmcentrez
There’s this paper http://www.pnas.org/content/104/18/7367.long Last I heard, there were still a few non-skinheads at the National Academy of Sciences, but perhaps I’m misinformed. I’d certainly hate to pass off any nonsense as information.
1) You should re-read the pnas paper, since it basically doesn’t say what you’re asserting it says and, at any rate, it was published before the most recent work on Neanderthal sequencing.
2) That Kim piece ID’d some problem with the initial genome project… but didn’t actually question, or in fact take a stand, on the issue of admixture, I don’t believe. Rather, it raised contamination issues.
3) A rough sequence has been done again, and there’s jus tno admixture. Common ancestor, sure, but no admixture.
So, no, you’re not misinformed…IF THIS WERE 2007! Get with the times, Guy!
can i at least get a shout-out for suggesting the topic? maybe a free t-shirt? a hug? something?
I live in San Diego, CA and the weather is always sunny here. I never get tired of it.
I used to snack on two or three organic carrots when I got home from work–until I tried to grow them in my vegetable garden. They are so slow to mature (and much herbier and less sweet). I realized I could never grow as many carrots as I was consuming–and that something was wrong with that picture. Now I see them as more of a sugary treat. That one realization changed my entire approach to eating. Well, err, at least to eating carrots!
I think that is a very interesting and logical way of judging how much of any one food an individual should eat. But… I can’t help but think that the amount of a food would be limited by how much we could gather, rather than how much we could grow.
I hate winter (especially this year) but I can’t imagine life without the changing seasons. As with so many other things, I think our individual adaptations are very different, and have been highly influenced by where our recent ancestors lived. Until a couple of hundred years ago, for mine that meant a damp, chilly place with limited sun (hence the very pale skin…) where getting fatty fish from the sea and estuaries was an important part of staying healthy. I think plutosdad is on to something with the D-lower-in-winter relating to increased illness…looking forward to seeing what else you have for us.
Last year we had 98″ of snowfall and quite a few collapsed roofs. This year we had just a little over 12″ – a virtual non-event winter for us! Sure glad my husband and I didn’t try to start our newest goal of being full-time RV’er snow birders! Looks like the best thing we could have done was to stay home in good ‘ole Spokane for this winter. Didn’t is just snow in Oklahoma the other day?
I believe outside temperatures affect our digestion and body’s needs. I was raised with macrobiotics (a bit different than the primal lifestyle
)My lifestyle has changed as I grow and learn and now I am a proud primal member. However, Simon Brown defines macrobiotics in, “Macrobiotics for Life”, as a way of listening to what your body needs whether that be: meat, dairy, citrus(even out of season), certain veg. or fruit, and feeding that intuition. I agree. Not the typical hardcore vegan/veggie definition, which is awesome. That being said routine is my vice, over consumption of certain foods in attempts to achieve primal is no good. Mark brings up an excellent topic especially for my Temperate climate zone in the north east with 4 seasons. Is it necessary to detatch from comforts and conveinence with something as simple as nuts in order get out of our heads and better communicate with our bodies? Your guess is as good as mine.
@plutosdad – I read an article the other week that suggested that people’s tendency to get cold and flu at certain times of the year have more to do with people staying inside when it’s cold, so they tend to share the same air and therefore germs. Not sure if that is all there is to it, as the article suggested, but it’s definitely something to consider.
Besides lower levels of vitamin D and closer contact indoors, another factor is viral longevity. Viruses tend to survive longer on colder surfaces than on room temperature ones. For example, the SARS virus lived up to two days on a room temperature surface, up to four on the inside of a refrigerator door, and indefinitely in a freezer.
Interesting post, a friend just referred me. I think our cells can adapt on the fly. It’s like a question of gasoline versus hydrogen fuel cells. Our cells can adapt but it’s up to us as to what are the byproducts of combustion.
I live in Minnesota too, and also wondered about seasonal eating! I’ve got a drawer full of overwintered turnips that look at me reproachfully every time I reach for those greens from California.
My gut instinct is, those Ice Age hominids ate whatever they could get their chilly little hands on during the winter months. Assuming they had nuts and tubers to draw on, they might have eaten more carbs then but (as the season wore on) fewer calories overall.
I seem to be bucking the trend in terms of wanting to move somewhere warm! I live in Queensland (Australia), which is warm/hot tropical climate with basically one and a half seasons (summer and not-quite-summer). I’m moving to Victoria (Australia) at the end of the year for various reasons, one of them being that there are actually four seasons. I’ve lived there before and I loved it. I’ll miss the abundance of tropical fruit, but then I should probably be weaning myself off them anyway
I look forward to an exploration of human dietary adaptation to different climates. Even though agriculture is a relatively recent change, lactose tolerance of one example of how human genes can adapt in a short period of time. Different ethnic groups have different genetic adaptations to acquire the same ability to digest lactose. I believe that my northern European ancestors evolved genes to adapt to seasonally available food sources just as they adapted very light skin to maximize UVB absorbtion.
As a kid growing up in Michigan, I was always confused on Groundhog Day when the news anchor would announce six more weeks of winter like it was a bad thing. I’m now happily transplanted in Virginia, with a balanced four-season climate that’s just right for me. The symphony of spring has started with cheerful yellow forsythias now in bloom.
If we are so adaptable then why can’t we adapt to the foods that according to the primal blueprint are no no’s? We are able to live virtualy anywhere on this earth and live off of what is there so why would it be against primal to eat so many naturally occuring foods in those diverse areas?
We can and do. Most people live well beyond the age of reproduction while eating the worst possible diet the Government can approve.
The price is paid after the age of maximum reproduction in most cases. Our genes don’t care about that.
Great topic. Looking forward to more. I live in a small town with a small grocery store. Our produce isle is about 20 feet long. Not a ton of choices. Winter is even harder to find any variety. Summer gardening is our best bet to get some choices. I’ve been wondering; gardening being agriculture, is there any “primal” gardeners out there? I’m surrounded by corn and wheat fields here in Nebraska. Hunting is great but the gathering is a bit carb heavy.
Think greens and lettuces, harvest year round..
Because here in S. E. Mass, (50 miles south of Boston) Surrounded by cities, bays, ocean front and farmland, all together, we are very much blessed, (or cursed..depending) The use of greenhouses and cold frames will enable one to produce greens year round.
Hey Julie, if you catch this, Im moving to Quincy. Don’t know the area if you have any good shopping tips or health stores, farmer friends etc. I’ld love to know! Ill check back.
Allison, I just caught your post! Where are you moving from? I don’t know Quincy all that well, but you have lots of choices, and depending on where you are coming from, closer proximity to farmers markets and such in the city..We have a few Whole Foods markets here…A New England Quirk is the fact that Providence(RI)is 18 miles away, Boston, an hour,New Hampshire 1 and 1/2 hours,(all from me) literally everything is, technically, local! But we need a day trip to go to Boston..LOL. Feel free to shoot me an emai at arj5150@comcast.net Good luck!
Fishing here is great, but weather dependent…and shellfishing as well..mussells were considered “poor man’s food” until plenty of Cape Codders survived the cruel winters on Bivalves, stored squash and apples! Turkey and cranberries, Later!
I live in Sweden, about the same lat as southern Alaska. Needless to say, we don’t get much sun in winter time.
Interesting is the fact that the inhabitants in these northern parts obviously have adapted to lower levels of vitamin D.
For example: we get a lot of refugees, many from Africa, and lately many of the women have encountered “the Swedish/Scandinavian disease”; many of their new born babies are autistic. This is as a result of rapid change in vitamin D intake, which previously was high due to the African sun.
I find this really interesting and I’m looking forward to reading more about this.
There are a lot of medical observations tied in with seasonality. For example, in the US, suicides peak in April. Why? Nobody knows.
If you are born in the winter in the US, you are more likely to develop schizophrenia.
The incidence of Multiple Sclerosis increases as you move north in the US.
(Thought to be related to sun exposure and Vit. D)
Then there is the phenomonenon, of course, of SAD: seasonal affective disorder—the winter blues.
(I’m in the mental health field, that’s why I know these things)
Sooze
I grew up in the interior of Alaska, some 100 miles south of the Arctic Circle. For 2-3 months in the winter, most people were at work or school during all of the daylight hours. Seasonal Affective Disorder was a big problem among people who had just moved to the interior from the Lower 48, or even from Los Anchorage. (Back then, Seasonal Affective Disorder was just called “cabin fever.”) For people who were born in the interior, though, the lack of daylight was just part of life, something to be tolerated like the May mosquitos and the January snotsicles.
The payoff to living in the interior north came during summer. Outdoor softball games at 11 pm, sans lights. Post-dinner canoe trips. Prime gardening weather — we could grow enough veggies to keep a family of 5 in veggies all winter, as long as we protected our crops from marauding moose. And, a teen with a curfew of “dark” could reasonably retort, “OK, see you in August.” But, I digress.
The key issue with a Primal diet should be freshness. The closer your food is to soil it was grown in or fed on, the more nutritious it will be. Flying in asparagus from Argentina is not Primal..