Demand pricing (also called dynamic pricing) is adjusting the price according to demand. More demand, higher price. It is being considered for movie tickets:

If a movie is hot, the price could rise to whatever the market will bear. For example, I’d have paid $20 per ticket to see “Avatar” in 3-D when it first opened; maybe others would have been willing to pay even more. As demand becomes clear through lower ticket sales, prices would drop. So “Avatar” might cost $15 a few weeks after opening, gradually making its way to $10.

The theory behind the Shangri-La Diet says that body fat is adjusted in a similar way. When food is abundant, the set point (which controls how much fat you have) goes up (= you store more fat). When food is scarce, the set point goes down. This is how many storage systems work, of course; they increase the amount stored when the price is low and decrease the amount stored when the price is high.

Perhaps one day weight control will be explained to children by telling them it is like the price of airplane tickets: “When more people want to go to Los Angeles, the price goes up. When more food is available, your set point goes up . . . “

Alex Chernavsky, whose Shangri-La Diet experience I described recently, has recorded his weight for almost ten years, with the results shown in this graph. During that period, he’s changed his diet and exercise several times.

The first change was to a low-carb diet (Atkins-like, with lots of meat and fat). He made this change after reading Gary Taubes’s New York Times article “What If It’s Been A Big Fat Lie?”. As advertised, the low-carb diet caused him to lose a lot of weight but — not as advertised — after about a year he started to regain the lost weight. For other reasons, he changed to a vegetarian and later a vegan diet. They slowed down the weight regain but did not stop it. In 2005 and 2006 he managed by walking a lot — in 2006, 90 minutes/day or more 5 or 6 days every week — to lose almost 30 pounds, but then his weight resumed creeping upward. Then he lost about 30 pounds due to the Shangri-La Diet. He did the diet by drinking 3.5 tablespoons of flaxseed oil instead of lunch. He drank a glass of water afterwards to get rid of the flavor.

I have never seen a weight record this long. It suggests several interesting points:

1. A low-carb diet, as advertised, quickly produces substantial weight loss.

2. Not as advertised, the weight loss is followed by regain after a year or so. This implies that studies of low-carb diets and weight loss need to last several years to give a clear picture of how much weight loss to expect.

3. Low-intensity long-duration exercise (walking for 90 minutes almost daily) causes substantial weight loss. This isn’t surprising.

4. … but it is surprising the effects of the exercise appeared to last at least a few years after the exercise was stopped. I have never seen this reported.

5. The Shangri-La Diet worked well. Alex did the diet somewhat differently than other people so it was not obvious this would be true.

6. After he stopped losing weight on SLD, his rate of weight gain was roughly the same as his rate of gain before he started the diet.

On the Shangri-La Diet forums I found a link to this:

A middle-aged man named Kainin has lost about 60 pounds since September (7 months) and described his experience in great detail. On Weight Watchers, he lost 40 pounds in 6 months before gaining it all back (plus 10 pounds more) — he started at 290, went down to 250, and back up to 300. On Nutrisystems, he lost 20 pounds in 6 weeks before gaining it all back. So the Shangri-La Diet has already helped him more than those two methods, not to mention being easier.

At the end of February, his BMI went below 35, the level indicating Morbid Obesity.

To celebrate I went to the local party store to look for a mylar balloon saying something like “Congratulations on being just Obese!” but found — NOTHING! The closest I found was a bereavement balloon that read “Sorry for your Loss”. Not exactly what I was looking for.

The roughly 100,000 posts on the SLD forums make the case for the diet far better than I ever could. Now, if I could just get rid of spammers …

Alex Chernavsky has kindly given me several years of weight data he collected by weighing himself daily. He read about the Shangri-La Diet in 2005 and several years later decided to try it. The graph above shows what happened: Starting at 222 pounds (BMI = 32), over 11 months he lost 31 pounds, reaching a BMI of 27. Since then — while continuing the diet — his weight has increased at roughly the same rate it was increasing before he started the diet.

He started by drinking olive oil and sugar water, switched to olive oil alone, and then, finally, to flaxseed oil alone of which he drinks 3.5 tablespoons/day (= 420 calories/day). He does not clip his nose shut when he drinks it but he washes his mouth with water afterwards. More about his method here.

Almost all weight-control experts would say these results are impossible: 1. Alex lost weight because he ate more fat. Fat is fattening say most nutrition experts. 2. Atkins dieters, who don’t say that, think the secret of weight loss is to reduce carbohydrate. Alex didn’t do that (and eats plenty of carbohydrate). 3. He didn’t restrict what he ate in any way. 4. He didn’t change how much he exercised.

Quite apart from how it contradicts mainstream beliefs, including Atkins, the data are remarkable because the change was so simple, small, and sustainable, the weight loss so large, the rebound so minimal, and data period so long.

An ordinary clinical trial has obvious advantages over such one-person data, such as more subjects and more data per subject. Less obvious are the advantages of this sort of data over clinical trials:

1. Long pre-diet baseline. Clinical trials never have this. It allows one to judge if weight increase post-diet, often called “regain”, is due to the weight loss or other factors. In this case the rising pre-diet baseline shows that other factors are causing slow weight gain over time.

2. Motivation. In a clinical trial, the motivations of the researchers and the subjects are different. The researchers want to measure the effect of an intervention; the subjects want to lose weight. If paid, they may want to make money. The difference in motivations causes problems. How closely the subjects obey the researchers and how truthful they are is usually hard to know. This data does not have that clash of motivations and incentive to lie.

3. Realism — what methodologists call ecological validity. These data, unlike clinical trial data, come from the situation to which everyone wants to generalize: people trying a diet by themselves at home without professional support or guidance.

4. Level of detail available. You (the reader) have access to something resembling raw data. In clinical trial reports, the data available is heavily filtered (e.g., shortened, simplified) and the nature of the filtering rarely described. For example, you rarely learn in any detail what the subjects ate. With this sort of data, but not clinical trial data, you can get a better sense of whether the results are likely to apply to you.

David Mandel, CEO of Alliance United Insurance Company, asks a very reasonable question:

Despite all the success stories [on the Internet] regarding the Shangri-La Diet, and the mainstream media stories in 2006 after the book publication, the diet never picked up and seems almost unknown today.

Whether this is right or wrong depends on expectations. In December, SLD got a great push from being on the website of Tim Ferriss’s Four Hour Body under the attractive title “Alternative to Dieting”. Tim’s book was published in December and registrations to the SLD forums jumped dramatically. Yet even before that, forum traffic was growing. Traffic of course grew when the SLD book came out, later shrank, and now — surprisingly — is growing again. My interpretation is that the initial growth was caused by mainstream publicity and blogs. The current growth is caused by word of mouth.

If I google “Shangri-La Diet” I get about 800,000 hits, a decent amount. “Sonoma Diet” — the book came out the same time as mine — gets 200,000 hits. “Eat Right For Your [Blood] Type” and “Eat Right 4 Your Type” get a combined 150,000 hits. That book was a huge hit when it came out in 1997. The usual pattern is Google hits go down, but SLD hits have gone up over the years.

On the other hand, given that my book contained a new theory of weight control that made about 100 times more sense than the usual ideas and led to counter-intuitive new ways to lose weight that actually worked and that obesity is often considered the world’s #1 health problem — yeah, it is “almost unknown” compared to what one might have expected.

I was wondering if you had any insight as to why it did not go viral, if nothing more from word of mouth from success stories sharing with everyone who will listen to their excitement. It seems all but impossible to me that something this simple, and universally successful which can benefit the masses has managed to not go mainstream in all these years. I am utterly baffled, and assumed there must be a big downside, but all my searching online has revealed nothing but the success stories and initial feedback, mostly from 2006 and 2007, and little since. I am just overwhelmed with curiously as to how this did not become the norm for everyone.

When my agent circulated the proposal for the book, one editor regretfully declined to bid on it because she said the book was “15 years ahead of its time.” Perhaps she was just being nice, but when people tried the diet, and it worked, they wouldn’t tell other people because the diet sounded crazy. Which means it really was far ahead of its time. Good Morning America filmed me for a short Freakonomics-related segment and they played it for laughs: crazy professor.

So that’s my explanation for why it has spread more slowly than one might have expected: fear of ridicule.