I've been slowly removing a lot of veggies and fruits from my diet and have been ramping up the fat and more 'exotic' cuts of meat to get more vitamins (like organ meats). I'm thinking that if we are supposed to eat any carb based foods, we should probably only eat them when they are in season. So stored tubers and fruits like apples should probably be out since nomadic hunters woudn't be root cellaring things. They would have only eaten stuff fresh out of the ground or off the tree... Mark's Daily Apple had a recent post on seasonality but I remember reading somewhere else that our insulin receptors are actually more efficient when sugary foods become available and less efficient in the winter when they aren't.
I believe this study is saying that theory but I am not a scientist :) http://cat.inist.fr/?aModele=afficheN&cpsidt=20999452 Maybe there are other studies somewhere too...
asked byMikeD (3641)
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on March 28, 2010
at 09:14 PM
I defer to Dr Tourgeman at Nephropal:
This link a search for "season" http://nephropal.blogspot.com/search?q=season from which I gleaned the following:
I always thought that it was interesting from an evolutionary standpoint, that the highest levels of Vitamin D in the body are in the summer which corresponds to the period of highest fructose intake (fruit). It is becoming very clear that fructose not glucose (i.e. starch) in high levels is detrimental to human health - the metabolic syndrome. The concept that the consumption of plenty of fruits on a daily basis year round is healthy is completely wrong in my mind. This concept truly contradicts the seasonal consumption of fructose by ancient humans. Fructose allowed for high energy intake for the purpose of weight gain and survival of winter periods
I suspect our ancestors would not travel far if sufficient food was available locally. And it is inconceivable to me that paleolithic man would seek out and expend energy just to eat a balanced diet. Only when forced to...but not habitually.
And Paleolithic man did not have airfreight.
on June 16, 2010
at 01:58 AM
I was told this quote second hand while discussing some lifting stuff so if it's not entirely accurate, I apologize. But the quote is from Bruce Lee (or inspired by Bruce) and is something to the effect of, "If you use a canoe to cross a lake and at the other side lays a mountain, do you carry the canoe up the mountain with you because it aided you previously? No, you leave it at the lake because it's a tool in water and a burden on a mountain side."
I find this quote useful when discussing a paleo outlook on life. Using the "What would Grok do?" approach to life decisions is a great starting point but eventually I think we all do need to realize that we live in the 21st century. There are some advantages that we can take advantage of and still produce optimal health that may not have been an option during the paleolithic age.
It makes sense, from a logical and I guess from an anthropological standpoint, to eat a lot of fresh, seasonal fruits and veggies, to load up on body fat for the coming winter. But in the 21st century, we still live active lives even during the wintertime. I think stressing seasonally fresh food is a great idea from a environmental sustainability standpoint, from an economic standpoint, and nutritionally peaked food standpoint. But what are we suppose to eat in January? We could eat a lot of meat but grass fed, free range animal products are pricey. The cheapest cut of meat at my local farm, outside of organ meat, is ground beef at $6/pound. And it only goes up from there. Meanwhile, Trader Joe's has organic apples for like .79 a piece. Yes, I am eating 18 grams of carbohydrates in that apple and yes, it was picked a week too early so that it would be shipped from California or Mexico but I am already spending $70 a week in groceries as it is. Not to mention eating excessive amounts of protein can throw off your fat burning system (by converting it into glucose).
So, for me personally, I try to make responsible out of season selections. I eat a lot of the same foods each week but I try to cycle produce in and out like a hunter gatherer might. Get different phytochemicals and nutrients with the variety. I don't have the time to count out every nutrient so if I eat a variety of natural, whole foods, I'm bound to hit my quota on almost all the important ones, especially if I target some supposed "super foods" regularly. I'll avoid things like berries out of season because organic blueberries in March are considerably expensive. IF they happen to be the right price, I will certainly buy them up but I focus on source, cost, and variety. It may not be Grok-optimal but there are still some health benefits to eating apples in January and I really enjoy apples so I'll take whatever tiny negative effect it has on me in order to enjoy my life and enjoy a really nutritious food.
on March 28, 2010
at 08:40 PM
It's an interesting theory but seems to be far from proven. There's a political agenda attached to the notion of local eating that isn't really concerned with individual health so I'm suspicious.
It looks like that study involved questionnaires, not randomized controlled trials, so there is no way of inferring causality i.e. symptoms of metabolic syndrome may change with season simply because people's consumption patterns change with season.
Edit: After reading that abstract more closely, the conclusion seems to me to actually be against the notion of seasonal eating. They found metabolic syndrome to be worse during the summer months. I would expect metabolic syndrome symptoms to improve in summer if you hypothesize that that's when humans should be consuming a lot of fructose.
Keep in mind that paleolithic humans were nomadic. The availability of specific fruits consistently travels south through north and back throughout the growing season -- you can see this by just reading on the package at the supermarket where this week's blueberries, peaches, etc. came from. It's not unreasonable to speculate that the movements of paleolithic humans would have coinciding with this somewhat. Also, at least in NJ, wild fruits and berries seem to have a much longer growing season than cultivated, local farmed fruits and berries (though this is purely anecdotal). In summary, I think the availability of wild fruits and berries would have been much greater to a nomadic paleolithic human than that of farmed, local fruits and berries to modern humans. Eating "in season" might make sense but I think "in season" needs to cover a much wider range than just local and I'm really not sure what the optimal range should be.
Oh, and I could've sworn that I've seen archeological sites found in caves that appear to be food storage (thanks to the cooler in-cave temperature)?
Edit: Just to clarify, I'm not advocating gorging on fruit year-round. I'm just saying that I don't think the seasonality argument is good justification for gorging on fruit (or anything else) just because it happens to be in-season. I think nomadic paleolithic humans would have been following the bags of meat around and that would have somewhat corresponded to the growth season for bags of sugar. Back then, fruit probably would've been less sugary and more sour/tart/acidic than what we get these days so I'm not sure how much gorging on fruit would've been going on back then.
on March 28, 2010
at 07:20 PM
Yes, it just makes sense doesn't it? Do you need to be a scientist to just know this is right? I just know I shouldn't be eating bananas in the middle of winter, period.
Hunter/gatherers would have eaten whatever they could find and the seasons would have TOTALLY, without exception, dictated what food was available, what state it was in (as of course, animals would also have been subject to this availability too, resulting in differing levels of fat in their bodies throughout the year) and what nourishment it afforded humans. In turn, this cycle would have continued back to what effect humans had on the land as they hunted and gathered.
Our bodies were and still are exquisitely tuned into the cycles of nature and so, it follows that the lengthening and shortening of the days and our bodies must move in an intimate dance with each other.
We can nurture this connection nowadays by letting sunlight fall on our skins and in our eyes all year round, by following the length of day and night (and the phases of the moon) by using natural lighting after dark and of course paying attention to signs in nature - for instance, when nuts hang off trees, we eat them.
There are still many things that science has not yet been able to 'prove' or perhaps does not need to prove.....but I would say, without doubt, that all your hunches are right.
on March 29, 2010
at 12:11 AM
Yes, only in my local area season- not FLAs or Chile's. It is a very important aspect of Paleo or primal eating, often overlooked. Another aspect is to eat less in winter after storing some fat from Omega 6 sources like nuts ( a fall fat), more in summer, especially lots of food with Omega 3s (a summer fat). To be Paleo you can't just buy what the super market sets out.
on March 28, 2010
at 07:27 PM
The answer is confounded by our supermarkets supplying a year round supply of fruits and vegetables from all over the world.
The more strict interpretation of paleo, is to only eat fruit when it comes in season in areas where it freezes....depending on your genetic heritage.
If your genetic heritage is European, then fruits and vegs should only be eaten after the growing season has been long enough for the plants to survive, ie, mid summer and autumn.
If your heritage is more equatorial then fruits and veggies are available almost year around.
Louisa has said she and her family eschew apples until autumn.
The study does say that metabolic syndrome does occur more frequently during the summer and fall.
Conclusion: Fasting insulin, insulin resistance and prevalence of metabolic syndrome were higher in summer than in winter. BMI and season were 2 major determinants of the variation in fasting insulin. The contextual impacts of seasonal variation in shaping metabolic syndrome or insulin resistance in populations need to be reemphasized.
So eat your meat and fat during the winter and then fatten yourself up with fruits and vegs in the summer in anticipation of the coming winter...if your heritage is European.