If you are what you eat, what does that say about "The Twinkie Diet" professor?

I've had a few questions on the "Twinkie Diet" that's been buzzing about the Internet, so here's a few thoughts...

The gist of the Twinkie business is that professor of human nutrition Mark Haub lost 27 pounds over 10 weeks by eating largely "junk food", like Twinkies. The "secret" was that he cut calories from 2600/day to 1800/day. Haub's point was to show "in weight loss, pure calorie counting is what matters most -- not the nutritional value of the food". This gets the "well DUH!" award for the month. Suppose you ate nothing at all. You'd be getting zero nutritional value. Do you think you might lose weight? Hmmmm, could be, doc.

The deeper issue here is apparent ignorance of people like professors of human nutrition about the basics of metabolic regulation. To first order, if you keep the macronutrient ratios about the same in your diet and reduce calories, you will also reduce the amount of insulin your body secretes in response to that food. As oft noted on this blog, insulin is a major metabolic hormone, governing a wide variety of processes having to do with the utilization and storage of energy, not the least of which is driving fat storage. More insulin means more fat storage. Less insulin means less fat storage. Drop insulin enough and on average more fat leaves the fat cells than is stored. The root cause of fat loss under calorie restriction is NOT simply restricting calories, but the result that calorie restriction has on your hormones, particularly insulin. For anecdotal evidence of this, you could ask a Type II diabetic who has to take insulin injections how hard it is to lose fat even by starving. More controlled experiments have been performed in animals. For instance, you can take an obese rat, keep it's insulin levels artificially high, and starve it. Said rat will literally starve to death while obese, consuming it's internal organs for energy, because the high insulin level effectively keeps fat locked up in fat cells.

So yes, of course, you can eat a calorie restricted diet of Twinkies and lose fat. But failing to understand how all of the metabolic dots are connected leads to several common backwards assertions made in the article, e.g. "Being overweight is the central problem that leads to complications like high blood pressure, diabetes and high cholesterol". Sure about that doc? Or do obesity, high blood pressure, diabetes, and high (LDL) cholesterol have a common cause, like say excess insulin? After all, there are skinny people with high blood pressure, diabetes, and high cholesterol. There are obese people who otherwise tape out as very healthy. So obesity is clearly not a cause, at least not the root cause. Insulin modulates a large number of genes, and so the precise set of symptoms a person experiences from hyperinsulinemia is going to be a function of their specific genetic makeup. A key test of a scientific hypothesis is its predictive power. The hypothesis that obesity causes Type II diabetes misses by tens of percent. But 100% of Type II diabetics are hyperinsulinemic, whether or not they are obese. Where would you put your money?

The key take-away here is that there is a large body of "health professionals" who essentially view the human body as a black box, and as such tend to come up with hand-waving and over-simplified "rules" linking various externally observable effects, like "calories in, calories out" (strictly true, but pointless because it makes no connection between cause and effect). As such, the recommendations of these people rarely rise above the level of old-wives' tales, in terms of the strength of evidence supporting them. When we "open the box", and begin to understand how the inputs and outputs are connected, and further how the body maintains control over metabolism and behavior in an attempt to maintain "health", things become much clearer. If your health expert has this knowledge, you are very lucky. Most are ignorant, and likely will remain so, as once a person deems themselves an "expert", they no longer feel the need to learn anything new (particularly if it contradicts their "expertness"). So it is going to be up to you to gain some measure of knowledge, so that you can make informed decisions for yourself.

If you are a person with any degree of scientific interest and background, then I hope you will have read "Good Calories, Bad Calories" (or a similar book) by now. If not, then shame on you for purposefully maintaining your ignorance. While no book (even a scientific textbook) has the whole story, GCBC does a fantastic job of delving into the very well-established metabolic science linking insulin and various health issues. As oft noted within, most of this stuff is not considered controversial at all. The processes by which insulin regulates fat storage have been established for decades. The gap is simply one of knowledge, where "professors of human nutrition", medical doctors, and the like either don't learn this stuff, or fail to connect the dots: what you eat affects your hormones, which affect biological processes like fat storage, which affect other hormones, which can ultimately affect what you eat. Behavior, after all, is just another manifestation of biology. So it's going to be up to you to educate yourself to some extent. If you're more of a right-brain person or otherwise find GCBC a daunting read, Gary Taubes' forthcoming book "Why We Get Fat" might be more up your alley.

But if you choose to remain ignorant, and blindly follow "expert advice", you deserve exactly what you get.