Thursday, June 26, 2014

Fatsville Revisited and the Metabolic Winter

A while back... say 7 years ago (what??), I found an article called Ten Roads to Fatville in NewScientist magazine and wrote a little blog post about it.

Since then, I've spent a hella lotta time at university, studying psychology, and then nutrition, and have often considered and reconsidered the main theme of that article, which is: our bodies may actually prefer intermittent hard times and manageable levels of stress. Everyone has heard of hormesis, right?

I've come to think that a life of unrelenting physical ease could be toxic. Yes, I'm here to encourage you to be less comfortable. I can tell this will be a popular blog post.

A few days ago I read this journal article: 'The Metabolic Winter Hypothesis', which discusses seasonal calorie fluctuations, mild cold stress and (briefly) circadian rhythms as mechanisms which historically countered obesity.  I decided it must be time to revisit the idea that, in many cases, unhealth is a condition of too much good stuff. Radical idea, isn't it?  First a little background about the clues in our physiology that support my perspective.

One of the difficulties with figuring out the 'perfect diet / lifestyle' is that the body is a master of adaptation. 'Perfect' is a constantly moving target. Popular health literature might give you the idea that the human system runs somewhat mechanically, taking in fuel and disposing of waste in a standardised way, with little variation in what happens between input and output.

Not so.  The body is genius. It's clever. It's cleverer than you, your vitamin pills and your diet books.

When investigating nutrient metabolism (particularly micronutients; macronutrients are a bit different), I became fascinated by the intelligence at play within the body. The functioning of nutrient receptors and transporters is truly amazing. I won't get into the sciency stuff today (because it's quite complicated and I might mess it up), but in summary, the cells of your body, including those in the gut, are festooned with devices that pick up nutrients (and hormones) and transport them into the cell. A good example is the VDR: vitamin D receptor which is found in nearly every cell. 

What is cool about receptors and transporters is that they are under genetic regulation and the body will upregulate or downregulate expression (numbers) of them depending on supply and demand. So, when a particular dietary nutrient is lacking, receptors and transporters are increased and you will absorb and store more of that thing. When there is lots of that same nutrient around, the opposite happens. Vitamin B12 is a very interesting example.  The body stores vitamin B12 very efficiently, often hoarding 3 or more month's worth in the liver.  I can imagine how this adaptation was useful to cavemen. You hunt down a massive beast, everyone chows down on meat and offal for a few days, restoring the B12 stores, and then you're all good if it's another month before downing the next mammoth.

Upregulation of receptors in times of deficit is why most micronutrient deficiencies resolve very quickly. The body is primed to deal with a deficiency as soon as that nutrient becomes available. This is also why it's smart to pulse your micronutrient supplementation. It doesn't take long for your cells to deduce that you have entered a time of vitamin abundance, downregulate uptake, and with callous regard for your finances, increase elimination of those pricey supplements.

Do you see where this is leading?

What all of this suggests is that the body expects times of lack and times of plenty and is not designed to be inundated with the same foods, in unlimited quantities, year round. I've noticed in the farmer's market that eating seasonally creates a natural ebb and flow to nutrient delivery. Berries are a good example.  There they are, berries everywhere, lots of antioxidants, vitamins and phytochemicals, and then they are gone for another year. At other times it's mostly hardy green veges, and a few winter fruits. The body knows how to store most nutrients efficiently when they are available, how to avoid storing too much, and how to release and use those stores when needed. There are a few exceptions there, for example vitamin C, which for some reason, doesn't accumulate - probably this indicates that our natural state is to consume it daily.  

We are great at stacking on fat in times of plenty, and using it in times of lack. We are also made to shiver in winter and sweat in summer.  We are made to release stress hormones when in danger, and then use them to fuel a physical escape.  This brings us back to the Ten Roads to Fatville. The problem is that our huge brains have figured out that scarcity, hardship and physical effort are uncomfortable, and should be avoided at all costs.  We eat overly-tasty foods without a break. We spend all day in air-conditioned comfort. We don't sleep enough (how can one sleep when Pinterest exists?). When stressed, we flop in front of TV, percolating in our own stress hormones, perhaps adding a bit of alcohol to the liver's burden. If we have a health problem, our approach is to add something (a pill, a potion), usually because someone is trying to sell it to us. Basically, we never really stop

In my opinion, this is where 'movements' such as paleo are slipping up, and why simple things like Intermittent Fasting, should be getting more attention (although again, you can be too dogmatic about that and it does not suit everyone).  Reading paleo/primal blogs is beginning to piss me off.  A paleo lifestyle (or any healthy lifestyle) is not about sticking to a list of approved items with little variation, or making complicated meals so that you can continue to overconsume without chubbing out. These things are also crucial:

* Sleep
* Social Relationships
* Intelligent Movement (and it doesn't have to be Crossfit)
* Stress Management and REST
* Unprocessed food 
* Not stuffing your face
* Time spent not thinking about food (it's 'eat to live', not 'live to eat')

When I read a 'primal living' blog that is full of more, more, more! (make this treat! buy this thing in a packet! 101 ways to use coconut flour! join our online forum! butter! bacon! coffee! do this workout! try keto! try safe starches! comment here and I'll tell you how to make paleoblissamazeoballs!!) I feel  a sort of despair.  

How about.. just stop. Button off. Eat less, but better, and with more variation.  Go for a walk in winter.  Get hungry now and then. Explore. Go to bed early. Kiss someone. Get sweaty. Punch your boss.

Ok, don't punch your boss. Violence is not the answer. ;)


  1. Honora11:59 pm

    Appreciated your well-written points and reminders. They're taken to heart so don't come visit us as our home is unheated! Tramping's good for getting outside of the comfort zone. Be great to read a post on intelligent movement.

    1. Yes, I must address that (movement). ;)


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