Another piece to the puzzle is how do fatty acids fit into this theory. First, we know that as the omega-6 to omega-3 ratio has gotten worse in the U.S. over the years, people's health has declined. The next question is how does this relate to the different seasons.
Prompted by an earlier commenter, I found this fantastic article by Susan Allport. She discusses how omega-3s are "spring fats" and omega-6 are "fall fats". Spring fats cause us to lose weight in preparation for mating season, while fall fats tell us to stock body fat for the upcoming winter. There are additional followup articles at Susan's website.
This idea about spring fats and fall fats leads to other connections. First, you can look at nuts, which are an autumn/winter food. Over at the Paleo Diet website, this table show the omega-6 to omega-3 ratio for various nuts. Almost all the nuts listed have a very high n-6/n-3 ratio. Is this just a coincidence that these fall foods have a high ratio? I doubt it. Most likely, the changing fat ratio in these fall/winter foods signals the body to store fat.
I don't want to make it sound like nuts cause obesity. In studies, nut consumption may produce only produce a small weight gain. The normal cycle of the winter metabolism probably only produces slight weight gain. It is the idea of a modern person being in a continual winter mode that could ultimately lead to obesity.
The next question is how available are omega-3s during the summer months. Another graph from the Paleo Diet website shows the changing fat levels of wild game over the season:
The omega-3 fats (polyunsaturated) are not that prevalent in the summer months. However, if you believe that seafood played a large role in the Paleolithic diet, then you have your answer as to why omega-3s are a summer food. Fatty fish with their high omega-3 content are most prevalent in the summer months.
There is one other way to tell if omega-3 fats are a summer food. You could find out if the consumption of omega-3s gives skin protection from the summer sun. As it turns out, they do. This document shows how omega-3 fats provide skin protection from "the inside out" in terms of UV radiation.
Overall, this shows how fatty acids may play a role in shifting the metabolism into winter mode. The modern diet tends to be low in omega-3s and high in omega-6s. Refined foods and junk food often contain vegetable oils, which have high levels of omega-6 fats. Shifting towards "spring fats" like omega-3s may facilitate weight loss.
Matt,
Thanks for the link to Susan’s site.
Don’t salmon (Om.3 super summer food) run in the spring?
Interesting stuff Matt.
Marc
Could be. I’m grouping spring/summer and fall/winter as two separate times in terms of metabolism.
If your data on carcasses separated the omega-3s and omega-6s (instead of grouping them together as polyunsaturates), you would see some revealing patterns.
I think you’d be interested in reading my articles, Seasons of Fats, posted on my home page http://www.susanallport.com
I’m so glad somebody else is thinking about these important changes.
Susan Allport
How does the body benefit from linolenic acid *directly* (other than for energy)–not considering the conversion to EPA, which is very small? I’m still not convinced that we need to eat any plant foods or use canola oil for the purpose of consuming omega-3. I will continue to take one teaspoon of lemon-flavored Carlson’s fish oil AM and PM, providing 2.6 grams EPA/DHA. I don’t use any omega-6 oils because it seems unnatural, but the Nurse’s Study and Walter Willett consider them very beneficial foods. And observational studies have found that high omega-6 intakes are irrelevant when using 2-3 grams of fish oil daily, at least regarding CVD issues. Then the low omega-3 in grain-fed meats and eggs, or minimal 100 mg DHA in eggs of flax-fed chickens are also irrelevant. Evidently, animals are much better at making the linolenic acid conversion to EPA/DHA than humans, so we need to consume them. For humans, the plants provide other benefits than omega-3. Susan Allport must think we can’t read critically.
Have you read about summer v. winter mode and the molecular mechanisms SIRT/FOXO v. AMPK?
http://nephropal.blogspot.com/2009/11/summer-vs-winter-mode-explaining-ampk.html
Both n-3 and n-6 are powerful hormones that control this and subsequent hormone cascades. DNA microarrays are showing that n-3 control hundreds of anti-inflammatory and neurological genes.
n-6 is not irrevelant — they have high biological half-lives of ~2.5 years. Many of us who have consumed hydrogenated oils may still be damaged from them for decades.
Good deal, I’ll check it out.
Thanks.
After reading some revealing Ray Peat articles and others on fish oil, I’m eliminating it and adopting the “Peat Diet” (animal proteins, fruit, tubers). Will use small amounts of veggies for flavor only, some chocolate, and maybe even some ice cream to address any calorie deficit. Even Susan Allport in an audio (pleasant speaking voice) questions the use of fish oil given our savanna origins. But the half-life of stored PUFA’s in human cells is over two years, which isn’t a happy thought. Down with all PUFA’s!
Down with PUFA’s? You are a Paleo rebel!
I will have to check out some of these Peat articles.
I thought polyunsaturated fats were found only in cold weather plants and animals like cold water fish. polys don’t freeze hence they are used for this purpose in the tissues of animals and plants, and that is why coconut oils are solid or saturated as saturated fats are stable in hot conditions.
os if your eating omega 3′s I would think this conveys the message you live in a cold weather area and need to get fat. our cellular membranes are fifty percent fat mostly saturated some mono and small amount of omegas.
these are turned over regularly as they become oxidized and damaged.
rosa