A 2010 study (via Whole Health Source) compared a Paleo diet with a Mediterranean diet. For twelve weeks, twenty-nine volunteers could eat as much as they wanted, whenever they wanted. Half ate Paleo (“lean meat, fish, fruit, vegetables, root vegetables, eggs, and nuts”), half Mediterranean (“whole grains, low-fat dairy products, vegetables, fruit, fish, and oils and margarines”).

The main result was that the Paleo food was “more satiating per calorie”. The Paleo eaters ate less but no more often than Mediterranean eaters. The paper does not report weight loss. (See an earlier report of the same experiment for that.)

I suspect the Paleo diet was less familiar than the Mediterranean diet (of course I can’t be sure from the descriptions). My theory of weight control says familiarity matters: less-familiar food pushes your set point lower than familiar food because its smell-calorie associations are weaker. The smells of less-familiar food is less associated with calories than the smells of more familiar food. With a lower set point, you will need less food to feel full.

If familiarity matters, this causes big problems for clinical studies. It means that short-term results (e.g., after 6 months) may be quite different than long-term results (e.g., after 2 years) — and most clinical trials last about six months. Short term, says my theory, any new food will cause weight loss. Indeed, a wide range of diets that cause dieters to eat new foods, such as the cabbage soup diet, cause short-term weight loss. Over the long term, however, the new foods become familiar and, according to my theory, the set point goes back up as the new smell-calorie associations are learned. Indeed, on most diets there is great long-term weight regain. If familiarity matters, we need data sets lasting a long time (e.g., nine or ten years) to understand weight control. Such data sets allow enough time for the chosen diets to become familiar so that (a) the diets being compared are equal in familiarity and (b) we can see their long-term effects — which may easily be different from their short-term effects.

Thanks to Steve Hansen.

After having guests over for dinner, my friend Carl Willat realized he had the ingredients for a root-beer float: Haagen-Daz vanilla ice cream and A&W root beer. He hadn’t thought about root beer floats in years. He made one. The next day he made another one. He ran out of root beer, bought some more. The day after that, another one. They seemed to taste better and better each day. He ran out of ice cream, bought some more. The next day, another root-beer float. The next day, another one. Toward the end of the week, he found himself thinking: When am I going to have one tomorrow? He had to force himself to stop buying ice cream and root beer, and after a while he didn’t think about them anymore.

At the heart of the theory behind the Shangri-La Diet is the idea that we learn to associate flavors (more precisely, smells) with calories. Here is a vivid example.

I’ve noticed this learning with liquor. A few months ago I bought my first bottle of rum — to flavor yogurt. Sometimes I drank the rum without yogurt, and it tasted better and better.

Pat McGee of Grand Prairie, Texas, learned about the Shangri-La Diet last week and realized the theory behind it explained something strange that had happened to him:

A couple of years ago I unpacked my scale and was astonished to see that I had lost 25 lbs sometime in the couple of years before that. [He went from 165-170 pounds to 140-146 pounds. He is 5 feet 8 inches tall.] I was mystified as to why, as I could point to no changes in anything I thought might be relevant in my life.

Last week, I found out about the SLD and read the first few chapters of the book. I realized that about three years ago, I had switched from sodas [with sugar, such as Coke and Pepsi] to weak iced tea. I did this mostly because I was feeling cheap and didn’t feel like paying for bottled sodas any more. I use 5 small teabags and a cup of sugar per gallon, steeped for about 6 minutes with a little lemon juice. Basically I want something that’s got just enough flavor that it’s not plain water.

When you are 5’8″ and 170 pounds, losing 25 pounds without trying (from BMI 26 to 22) is astonishing. Not only that, he has kept it off. His story is a little different than mine because I didn’t stop drinking anything — certainly nothing as fattening as Coke or Pepsi.

Here is a new use of the ideas behind the Shangri-La Diet — namely, identifying what caused massive accidental weight loss. Obviously others can use his discovery. From a theoretical point of view, he replaced strongly-flavored drinks with a weakly-flavored one. According to conventional ideas about weight control, this should have no effect.

It is also an interesting example of behavioral engineering because he switched from standard soft drinks (such as Pepsi) to his concoction without difficulty. His drink was pleasant enough. It derived pleasure from flavor (tea), sweetness (sugar), and sourness (lemon juice). A little salt would have allowed him to reduce the flavor even more.

Over at the SLD forums, Newbie Numpty has lost about 50 pounds in four months. His starting weight was 320 pounds. Recently he reported:

My wife tells me that I have stopped snoring – this is something I’ve done for years (decades) so it could actually mean that I am now at a lower body fat that I have been for a number of years – no way to tell. But a great thing for sleep quality – I’ve spent money on nose strips and mandibular extension devices to help with this, SLD is again a cheaper fix!

Seeing Alex Chernavsky’s ten years of weights inspired David Hogg, a professor of entomology at the University of Wisconsin, to send me his weight data for the past nine years — see above. Like Alex, he found that the Shangri-La Diet worked where other methods failed.

He is 5′ 10″ and 63 years old. When his weight reached 205 pounds (in 2002) he decided to take serious action. He began by increasing how much exercise he did, to “watch what [he] ate,” and to take “diet” pills. I asked him about the diet pills. He replied:

On [the advice of a local supplement store owner] I began to take L-Carnitine, which has a variety of effects (including some evidence for weight loss?), and an ephedrine based diet supplement (I don’t recall the name of the product). I took the ephedrine until its sale was outlawed (2006?), after which I started taking a NOW Foods product called Diet Support, which lists as major ingredients iodine, chromium, forskolin (from Coleus root), L-Carnitine, extract of Garcinia cambogia, green tea extract, and extract of Uva ursi leaf.

He described “watching what [he] ate” like this:

I started having a fruit smoothy with protein powder and flaxseed oil for breakfast (rather than eggs/cereal and toast) and I cut back from a full sandwich and fruit to a half sandwich and fruit for lunch. I did not modify what I ate for dinner but did attempt to eat less, and I tried to not snack between meals. I think all of this was somewhat successful, although I was hungry a lot and suffered regular setbacks.

He described his exercise like this:

My goal was to get some form of exercise daily. In reality I probably get exercise on average 5 days a week, but this was not too different than what I was doing previously. My primary means of exercise are bicycling and racquetball/squash, but I also golf (walking, not cart) and take a range of classes at a local health club that includes Pilates, spinning, and weight lifting.

In 2002 he increased how much exercise he did.

In 2002, in other words, he began to do conventional weight-loss things (eat right, eat less, and exercise more) plus take diet pills. This lowered his weight from 205 to 180 but not further, even though continued for years. So far the Shangri-La Diet has lowered his weight about 10 pounds. He does it like this:

I started out with sucrose water, after several weeks switched to ELOO (which did not seem to work for me, perhaps because it reminded me of popcorn?), quickly switched to fructose water, which I used exclusively for 6+ months, then switched again to walnut oil (the fructose water made me feel bloated). For the past approximately 4 months I have added fructose to the walnut oil, which I started to use up the large supply of fructose I ordered, but it actually seems to work the best of anything I’ve tried to date. I drink 2 tablespoons of walnut oil containing about a quarter of a tablespoon of fructose, twice daily.

My ideas about dietary control of the set point made a lot of sense to him.

At one time I believed weight gain or loss was purely a matter of calories in vs. calories burned. Up to age 30 that model seemed to explain my weight. After 30 it was not so simple, with my weight seemingly resistant to sustained loss or (in the short term) gain, and this led me to adopt the view that my weight was governed by an equilibrium or set point. This was easy for me conceptually. My professional interest at the time was insect population dynamics, and the prevailing view was that although insect population densities fluctuate (sometimes widely) through time, for a given species the fluctuations tend to occur around an equilibrium that is enforced through density dependent processes. However, I viewed my set point weight as “fixed”, so my paradigm did not explain the upward drift in set point and weight. Your discussion of this, from an evolutionary perspective, made me rethink my idea of a fixed set point and provided the perfect explanation for the upward drift in my weight (plus the way to convince the brain to decrease one’s set point).

His data are an important advance in understanding. They cover a long period of time and allow comparison of the Shangri-La Diet to three popular weight-loss methods: “controlling what you eat”, exercise, and various supplements (“diet pills”). No conventional weight-loss experiment covers as long a period of time.