We Have a Controversy!

My friend Blake had the following to say about carbs and cholesterol. I'm hoping he'll read the Taubes book and help us all make sense of it!

"Hey Tess, this is obviously unsolicited, so sorry and feel free to ignore. I do teach metabolism, and have thought a bit about all this, not that I'm positioning myself as an Authority. But reading your post, well it made me think. What I will say overall is that its really hard for *anyone* to look at the nutritional science of the past 10, 20, 30 years and come up with definitive conclusions. I'm pretty suspicious of attempts to do so, though obviously an Answer is what everyone is after. Not that scientists are the only ones who can/should interpret the science, either...
Anyway, as to insulin:
Insulin's job is not to store fat. Its job is really to respond to sugar concentrations in the blood, and one of its principal duties is to induce import of glucose into the cell. When there's a dietary influx of carbohydrates (like the chocolate chip cookies I've been working through), that's a signal that the 'fuel level' is high, and it's time to store it away for future use. On the one hand, insulin induces storage of carbohydrates as glycogen (particularly in the liver). On the other hand, when glycogen levels are adequate, insulin stimulation leads to synthesis of lipids. This is the trouble! Excess carbohydrate is going to be stored as fat... the simplest-to-grasp reason is that, calorie-for-calorie, fat takes up less space... fat doesn't have to be bathed in water, like carbohydrate polymers such as glyogen do... for this and other reasons, fat is a better energy storage medium. Also, the liver has limited glycogen storage capacity, whereas we have lots of adipocytes for storing fat distributed all over the body. There are other effects of insulin on gene expression, etc... In the end, insulin is part of a 'homeostasis system' that works to keep energy levels constant. Incidentally, that tendency towards homeostasis makes it hard to lose the weight we've gained.
So insulin is good! Import of carbohydrates is good! Storage of glycogen and lipids is good! Loss of sensitivity to insulin (and the resulting health problems including perhaps obesity and CHD) is most likely the result of difficulties that arise from chronic overingestion of calories (of carbohydrates perhaps most specifically, but of food in general) and concomitant underconsumption (use of) those calories in exercise.
As for the Western diet, I just wanted to say that indigenous American and Asian diets are not lacking in carbohydrates: those non-western cultures gave us corn and rice, after all! Again, my impression is that it's this over/under problem that leads to issues of obesity, and thence to the other problems... As for the refined carbohydrate thing, I tend to think of it like I do the high-fructose corn syrup thing. Fructose is fructose - it all goes into the same energy production pathway - the problem is the amount of it we ingest. All plant fuel storage carbohydrates are made of glucose, and glucose is what insulin causes to be imported into the cell, whether the grain has had the bran removed or not. We just need to eat less of them to avoid storing them as fats.
I guess I just wanted point out that it's not carbohydrates per se that lead to insulin dysfunction, but overconsumption of these and other foods. Our lives depend on carbohydrates. Too, I think (having not read the book) that statement about 'everything we believe about a healthy diet is wrong' could be a bit hyperbolic. What's really problematic, I tend to think, is the search for a diet 'Answer' other than moderate eating and exercise (this, from a fat, lazy hedonist).
The books may have covered all this stuff, and I'm just being a didact (in fact, I know I'm a didact, so f@$& me!). I have enjoyed your blog... and the Taube book's in our library, so I'll check it out... I hope you don't mind my note, though, and I won't mind if you tell me to piss off! I totally respect your quest... my own quest focuses on finding time to do anything resembling exercise. Hopefully you take or leave my input without getting to irritated with me!"

Meanwhile, here's an article from the LA Times that summarizes what I've read better than I ever could:

http://www.latimes.com/health/la-he-carbs-20101220,0,5464425.story