My, my, my! Leave it to Stephan Guyenet and Gary Taubes to keep things interesting since their spat at the Ancestral Health symposium last month. Stephan had responded to Taubes’ latest, but curiously has taken down his post which, IMNSHO, was unfairly criticized by Taubes’ devotees (bummer, too, it was driving a lot of traffic to my blog for this 1796 recipe for ‘diet bread‘ ;).
Better late than never, this has prompted me to go on the record about where I am with carbs. In a word, I’m agnostic. Or perhaps the more apt religious metaphor is that I prefer to follow the middle way.
Simply stated: I don’t demonize carbs, but I think our Western diet full of refined carbs is not healthy.
My low-carb past
I come to this position with a somewhat unique perspective. I’ve actually lost a boatload of weight LCing. Twice. The first time was in my late teens between my freshman and sophomore years of college, back when Nutrisystem was a ketogenic diet; I lost 75 lbs over that summer. The second time was in my 30s, when I lost over 100 lbs doing a medically supervised liquid fast.
And LCing certainly worked (at least temporarily). I did find that ketosis seemed to suppress appetite and providee energy. But I struggled to do LC over the long haul (which seems to happen to others as well).
So, here I am a couple of decades later, hopefully losing weight for the last time … and this time, I’m taking a different route.
Moderate carbs for me!
I’m approaching carbs moderately, because I think it’s something I can sustain for a lifetime. I also suspect that eating different levels of carbs may be a good strategy.
Here’s Mark Sisson’s carboyhydrate curve:
On a typical day, I like to stay in Mark’s “weight loss sweet spot” of 75-100g of carbs. But at least once a week, I eat somewhere in the 100-200g range for diet variety and to keep my carb machinery working. I also like the idea of a periodic postprandrial leptin boost … a la Leangains’ carb refeeds.
A word about flexibility: If you’ve read many LC blogs or forums, you’ve probably come across the advice to ramp up carbs before an OGTT or else you’ll be diagnosed as a diabetic due to sky-high BG readings.
Basically, the gist is if you go LC long enough, you down-regulate some of the enzymes needed to metabolize glucose, thus your BG levels go higher during an OGTT (or if you had a high carb meal while LCing) than if carbs were a normal part of your diet. This is essentially the opposite of the LC induction ‘flu.’
For me, eating moderate carb lets you keep your metabolic flexibility. That means not so many carbs so you are primarily a sugar burner, but not too few carbs so you can only be a fat burner.
IMO, this flexibility makes for a great “for life” diet. Another plus: I don’t have to worry about potential low-carb thyroid issues.
Chicken or egg?
While we’re on the subject of carbs, I think yesterday’s tweet from Chris Kresser bears repeating:
Also, if I hear another person say “LC diet worked for me, so the insulin hypothesis must be correct” I’m going to flip out.
To me, this is an important concept. No one disputes that many people find LCing a useful way to lose weight (at least in the short term). But many of the studies touted by the LC camp also show that many people do not do well on LC — sometimes because of compliance issues, or sometimes because they seem genetically wired to need more carbs.
Brain or booty?
This snippet of a conversation between Dr. Mike Eades and Dr. Emily Deans on Twitter today really framed the discussion in a way that gets at the heart of the matter: where is the source of the dysfunction … fat tissue or the brain?
Good question!! I can’t wait until we find out … hopefully in my lifetime.
[As an aside, I suspect that the combination of carbs AND fat is a problem ... especially when you're talking refined carbs and sugar and refined veggie oils. This not-found-in-nature combination is not only problematic from a brain/food reward perspective but also from a downstream perspective (e.g., hepatic injury).]
I’ve also become intrigued by the idea of a seasonal approach to carbs. It makes sense to me from an evolutionary perspective: my northern European ancestors probably cycled between a low (or no) carb diet in the winter months and a higher carb diet at the end of the summer. And this may or may not be related to serum vitamin D levels which likewise would have varied seasonally.
Interestingly, Robert Lustig has a theory that higher fructose intakes might create insulin resistance (for example, at harvest time) to enable us to put on fat stores to help us get through the winter.
Of course, this doesn’t work so well in our modern food environment, which is all harvest, all the time. Living seasonally — or perhaps alternating periods of “feast” with “famine” might be an interesting tack to take.
Your mileage may vary
All of this said, note that I titled this post “why I eat moderate carb” not “why you should eat moderate carb.” I read very many LC (and ZC) blogs, and they make compelling arguments for a low-carb diet. If they work for you, great!! Keep on keeping on ;).
Update, 9/5: Chris Kresser adds some useful context, Reframing the obesity debate: cause/effect, genetics & robot clones
Update, 9/6: Yoni Freedhoff asks (and answers correctly IMO) the question: Will there ever be a grand unified theory of obesity?