Tea, Wine, and Chocolate: A Puzzle

Last night I went to the opening of the lovely Teance store on Fourth Street (Berkeley). Teance specializes in Asian teas, with some Indian teas as well. They used to be elsewhere in Berkeley, but their lease ran out. At the new location, they replace a gift shop, which makes sense: Fourth Street is foodifying. Teance fits well with the other upscale food stores in the area, such as the Pasta Shop.

But enough about small business. At the opening, someone from a local tea appreciation society gave a brief talk. Two things he said made me think. One was: “We drink tea for fun. The health benefits are just a bonus.” The other was a comparison of tea and wine. Tea is now where wine was thirty years ago. Since then there has been a vast increase in wine appreciation. “Thirty years ago if it was a special occasion you drank a bottle of Blue Nun. Now every kid on a skateboard knows the difference between merlot and cabernet sauvignon.”

Wine has health benefits, of course. A few weeks ago I went to a little tour/talk/demonstration at Charles Chocolates in Emeryville, where a few of the fine points of making chocolates (the candies, not the raw ingredient) were explained. Chocolate, too, has health benefits, as the makers of Cocoavia will be happy to explain. (Charles Chocolates has partnered with Teance to produce a line of tea-flavored chocolates, which were served at the opening.)

Three foods with intense connoisseurship action, three foods with substantial health benefits:

1. Wine

2. Tea

3. Chocolate

A coincidence? Or meaningful? Will cheese turn out to have health benefits? As a general rule, connoisseurship and health are unrelated: That hand-painted Italian flatware is no better for you than K-Mart’s finest (at least before the partnership with Martha Stewart, who called their customers “K-Martians”.)

I became interested in connoisseurship because of my interest in human evolution. Connoisseurship evolved, I believe, because it supported high-end craftsmanship. Skilled craftspeople were the main source of technological innovation. Connoisseurs happily pay more for high-end, carefully-made stuff. The tea spokesman was right: We drink it for fun.

Grass-Fed Beef, the Shangri-La Diet, and the Future of Food

A recent Slate article compared beef from different sources. “We sampled rib-eye steaks from the best suppliers I could find. The meat was judged on flavor, juiciness, and tenderness and then assigned an overall preference.”

The winner: grass-fed beef, which was also the least expensive ($22/pound). The highly-convincing tasting notes:

Never have I witnessed a piece of meat so move grown men (and women). Every taster but one instantly proclaimed the grass-fed steak the winner, commending it for its “beautiful,” “fabu,” and “extra juicy” flavor (that “bursts out on every bite.” The lone holdout, who preferred the Niman Ranch steak, agreed that this steak tasted the best, but found it a tad chewy.

The grass-fed beef was probably the highest in omega-3, by the way. What the writer found wrong with grass-fed beef was lack of consistency:

One grass-fed rancher I spoke to refused to send me any steak for this article because, he said, it sometimes tastes like salmon. Restaurants and supermarkets don’t like grass-fed beef because like all slow food, grass-fed beef producers can’t guarantee consistency-it won’t look and taste exactly the same every time you buy it.

From the standpoint of the Shangri-La Diet, of course, variable flavor is a plus — a big one. I expect a similar result with other foods — the more variable foods taste better. As any engineer knows, the less you have to worry about keeping a variable (such as flavor) constant, the more you can do to maximize it.

Thanks to Clyde Adams for the link.

More Evidence That Fat Is Not Bad For You

In the most recent issue of American Journal of Epidemiology (15 November 2006) is an article about whether there is a connection between dietary fat and breast cancer. They found no connection. Part of the abstract:

Dietary fat in midlife has not been associated with breast cancer risk in most studies, but few have followed women beyond one decade. The authors examined the relation of dietary fat, assessed by repeated questionnaires, to incidence of postmenopausal breast cancer in a cohort of 80,375 US women (3,537 new cases) prospectively followed for 20 years between 1980 and 2000. The multivariable relative risk for an increment of 5% of energy from total dietary fat intake was 0.98 (95% confidence interval: 0.95, 1.00). Additionally, specific types of fat were not associated with an increased risk of breast cancer.

Reference: Dietary Fat and Risk of Postmenopausal Breast Cancer in a 20-year Follow-up. Esther H. J. Kim, Walter C. Willett, Graham A. Colditz, Susan E. Hankinson, Meir J. Stampfer, David J. Hunter, Bernard Rosner, and Michelle D. Holmes. Am. J. Epidemiol. 2006 164: 990-997.

How Well Does the Shangri-La Diet Work? (part 2)

The Post Your Tracking Data Here section of the SLD forums now contains lots of data. In addition to the weight-vs.time graphs on the home page and in the forums, I have now analyzed this data in other ways. The graphs below (based on data up to November 2) show how the rate of weight loss varies with (a) time on the diet and (b) weight.

For each person reporting weights, I computed a rate of weight loss for every interval in their data. For example, if someone reported her weight at three different times, then there are two intervals: from Time 1 to Time 2, and from Time 2 to Time 3. For each interval I computed a rate of weight change. The scatterplots below are based on 820 intervals. Each point is a different interval.

The first graph shows how the rate of weight change varied with how long you have been doing the diet.

This shows that average weight loss slowed down from about 2.2 pounds/week to about 1 pound/week during the first few weeks and didn’t change much after that.

Another obvious factor that might affect weight-loss rate is weight: Perhaps people who weigh more lose faster. Because rate of weight loss changes during the first few weeks, I looked at this question two ways: using only data for Week 1 on the diet (early loss); and using only data after 4 weeks on the diet (later loss).


The top graph (early loss) shows that during Week 1, your weight has a big effect on your rate of weight loss. People who weigh more lose faster. The bottom graph (later loss) shows that after 4 weeks, your weight has much less effect on how fast you lose.

My explanation: During the first week or so of SLD, most of the weight loss is not fat or water but the food in your digestive system. Because the diet has reduced your appetite, you are eating less each day. But the speed (inches/day) at which food travels through your digestive system does not change; so relatively full digestive system is slowly replaced by a relatively empty one. After this replacement — which takes about one week — is complete, further weight loss is all due to loss of fat. You comfortably lose fat at the rate at which your set point goes down. The long-term rate of weight loss is about 1 pound/week because the set point is going down about 1 pound/week.

Data analyses like these have never been published for any weight-loss method. Not that they’re sophisticated or clever or surprising — they’re not. Given (a) the amount of damage caused by obesity and (b) the amount of money spent on health research (2006 NIH budget: $28 billion), it’s quite a gap. Possibly related to the misguidedness I discussed last week.

Amazon Rank: The Poor Man’s BookScan

Calling all authors!

If you have written a book, you have probably wondered: What’s the connection between amazon rank and number of books sold? Well, wonder no more. Below is a graph based on The Shangri-La Diet. The copies-sold information is from Nielsen BookScan. Their website says:

Most of the nation’s major retailers for books are included in our panel of reporting book outlets: Borders and Walden, Barnes & Noble Inc., Barnes & Noble.com, Deseret Book Company, Hastings, Books-A-Million, Tower Music and Books, Follett College stores, Buy.com and Amazon.com. Weekly sales information is also tracked from Mass merchandisers like Target, Kmart and Costco, along with smaller retail chains and hundreds of general independent bookstores.

The graph shows that the relationship between books sold and amazon rank is linear on a log-log scale (as so many things are — the physicist Per Bak wrote a whole book about such relationships). Each point is a different week. To illustrate the formula of the line,

ln(copies sold/week) = 9.67-0.53*ln(amazon rank),

the amazon rank of Send In The Idiots: Stories From the Other Side of Autism by Kamran Nazeer, a masterpiece about the adult lives of autistic children, is now 35,758. Predicted sales is 61 books/week.

The Trouble With Rigor

This is an easy question: When writing down numbers, when is it bad to be precise? Answer: When you exceed the precision to which the numbers were measured. If a number was measured with a standard error of 5 (say), don’t record it as 150.323.

But this, apparently, is a hard question: When planning an experiment, when it is bad to be rigorous? Answer: When the effort involved is better used elsewhere. I recently came across the following description of a weekend conference for obesity researchers (December 2006, funded by National Institute of Diabetes & Digestive & Kidney Diseases):

Obesity is a serious condition that is associated with and believed to cause much morbidity, reduced quality of life, and decreased longevity. . . . Currently available treatments are only modestly efficacious and rigorously evaluating new (and in some cases existing) treatments for obesity are clearly in order. Conducting such evaluations to the highest standards and so that they are maximally informative requires an understanding of best methods for the conduct of randomized clinical trials in general and how they can be tailored to the specific needs of obesity research in particular. . . . We will offer a two-day meeting in which leading obesity researchers and methodologists convene to discuss best practices for randomized clinical trials in obesity.

Rigorously evaluating new treatments”? How about evaluating them at all? Evaluation of new treatments (such as new diets) is already so difficult that it almost never occurs; here is a conference about how to make such evaluations more difficult.

This mistake happens in other areas, too, of course. Two research psychiatrists have complained that misguided requirements for rigor have had a very bad effect on finding new treatments for bipolar disorder.

More Reason to Crazy-Spice

Spices are good for you, I blogged, because they are high in antioxidants. A new study, done in Singapore with elderly subjects, supports this conclusion. It found that curry-eaters do better than others on a mental test. The abstract:

Curcumin, from the curry spice turmeric, has been shown to possess potent antioxidant and antiinflammatory properties and to reduce ß-amyloid and plaque burden in experimental studies, but epidemiologic evidence is lacking. The authors investigated the association between usual curry consumption level and cognitive function in elderly Asians. In a population-based cohort (n = 1,010) of nondemented elderly Asian subjects aged 60-93 years in 2003, the authors compared Mini-Mental State Examination (MMSE) scores for three categories of regular curry consumption, taking into account known sociodemographic, health, and behavioral correlates of MMSE performance. Those who consumed curry “occasionally” and “often or very often” had significantly better MMSE scores than did subjects who “never or rarely” consumed curry. The authors reported tentative evidence of better cognitive performance from curry consumption in nondemented elderly Asians, which should be confirmed in future studies.

Tze-Pin Ng, Peak-Chiang Chiam, Theresa Lee, Hong-Choon Chua, Leslie Lim and Ee-Heok Kua. Curry Consumption and Cognitive Function in the Elderly. American Journal of Epidemiology 2006 164(9):898-906

Too Few Riders, Too Many Stolen Bases

I heard two excellent talks last week. Bent Flyvbjerg, a professor of Planning at Aalborg University, Aalborg, Denmark , spoke on “Survival of the Unfittest: Why the Worst Megaprojects [subways, airports, bridges, tunnels] Get Built.” Why? Because of false claims. Cost estimates turn out to be much too low and benefit estimates (such as ridership) much too high. Boston’s Big Dig, for example, has already cost more than three times the original estimate. Cost estimates were too low in 90% of projects, Flyvbjerg said. The tools used to make those estimates have supposedly improved a great deal over the last few decades but their accuracy has not improved. Lovallo and Kahneman have argued that the underlying problem is “optimism bias“; however, Flyvbjerg believes that the problem is what he now calls strategic misrepresentation — when he used the term lying people got upset. The greater the misrepresentation, the more likely the project would be approved — or rather the greater the truth the more likely the project would not be approved. That is a different kind of bias. An everyday example is me and my microwave oven. Sometimes I use my microwave oven to dry my clothes. I’ve done this dozens of times but I continue to badly underestimate how long it will take. I guess that a shirt will take 8 minutes to dry; it takes 15 minutes. I know I underestimate — but I keep doing it. This is not optimism bias. Microwaving is not unexpectedly difficult or unpredictable. The problem, I think, is the asymmetry of the effects of error. If my guess is too short, I have to put the shirt back in the microwave, which is inconvenient; if my guess is too long the shirt may burn — which corresponds to the project not being approved.

Incidentally, Flyvjberg has written a paper defending case studies and by extension self-experimentation. He quotes Hans Eysenck, who originally dismissed case studies as anecdotes: “Sometimes we simply have to keep our eyes open and look carefully at individual cases — not in the hope of proving anything but rather in the hope of learning something.” Exactly.

The other excellent talk (“Scagnostics” — scatterplot diagnostics) was by Leland Wilkinson, author of The Grammar of Graphics and developer of SYSTAT, who now works at SPSS. He described a system that classifies scatterplots. If you have twenty or thirty measures on each of several hundred people or cities or whatever, how do you make sense of it? Wilkinson’s algorithms measure such properties of a scatterplot as its texture, clumpiness, skewness, and four others I don’t remember. You use these measures to find the most interesting scatterplots. He illustrated the system with a set of baseball statistics — many measurements made on each of several hundred major-league baseball players. The scatterplot with the most outliers was stolen bases versus age. Stolen bases generally decline with age but there are many outliers. Although a vast number of statistical procedures assume normal distributions, Wilkinson’s tools revealed normality to be a kind of outlier. In the baseball dataset, only one scatterplot had both variables normally distributed: height versus weight. These tools may eventually be available with R.

David Jenkins on the Shangri-La Diet

David Jenkins, a professor of nutrition at the University of Toronto, invented the glycemic index, probably the most important nutritional innovation of the last thirty years. The glycemic index helped me permanently lose 6 pounds (see Example 7 of this paper). While preparing her CBC piece about the Shangri-La Diet, Sarah Kapoor interviewed Jenkins. Here is a partial transcript of what he said.

The Writing Cure

I wonder how many bloggers know about this — research about the beneficial effects of journal writing. James Pennebaker, a professor of psychology at the University of Texas Austin, has done a lot of research in this area. Here is a list of studies. This article sums it up nicely: “Writing about important personal experiences in an emotional way for as little as 15 minutes over the course of three days brings about improvements in mental and physical [!] health. This finding has been replicated across age, gender, culture, social class, and personality type.”

I’m guessing this research started as a search for the crucial ingredients of psychotherapy. What happens during psychotherapy that helps people? Early research found that the therapist’s training made no detectable difference. This suggested that just telling one’s story was therapeutic. Journal writing is another step in the same direction: You tell your story without anyone listening. Next step: studying the health effects of blogging.

The Annotated Woman’s World article

The next issue (Oct 3) of Woman’s World, already available many places, has a lovely cover story (pp. 18-19) about the Shangri-La Diet with the funny title “Instant Willpower!” The article is very accurate and reasonable but I have a few comments.

“Lose 7 lbs a week!” (cover and p. 19). Average weight loss is 1-2 lbs/week.

“Makes your body release stored fat!” (cover). Clever. I would have said something plodding like “lose body fat.”

“Roberts says refined walnut oil and light olive oils are best” (p. 18). Refined walnut oil is hard to find. I buy Spectrum refined walnut oil at Whole Foods. The Spectrum Organics store locator will find stores that carry Spectrum products but not all carry refined walnut oil. In Berkeley, most don’t. You may want to call ahead.

“When reading scientific journals to prepare for a lecture, Roberts had a eureka moment. . . Turning this interesting idea into practical weight-loss advice took lots of trial and error. . . . In short order, he was 35 pounds slimmer” (pp. 18-19). I lost 35 pounds using sugar water, not oil. It took three months. The turning point in going from theory to practice was a strange experience in Paris, described in the book. Also crucial was Emily Mechner’s observation that if my theory was correct, flavorless oils should work as well as sugar water. All in all, though, this is a good summary.

[to make this plan work even better] “Stick with your normal foods” (p. 19). No, I think the diet works better if you start eating foods that are new to you — foods with unfamiliar flavors.

“Avoid flax, unrefined walnut and extra virgin olive oils, which have strong flavor, says Roberts” (p. 19). You can drink these oils if you close your nose (using a noseclip for example) while drinking them. That will eliminate the flavor.

Seymour Benzer (crippling medical school research)

In an interview, Seymour Benzer, the great Caltech biologist, told a story that I think explains a lot about medical-school research, including UCLA medical school professor John Ford’s complaint about The Shangri-La Diet:

Harold Brown [president of Caltech 1969-1977] made himself quite conspicuous by . . . trying to develop a medical school relationship. . . . His idea was for Caltech to pair up with UCLA to make a medical school. We would do the first two years of basic education of the medical students, and afterwards they would be guaranteed two more years of clinical experience at UCLA. And then they could be doctors. . . . In the Biology Division, it went over like a lead balloon: Why should we be knocking ourselves out teaching these guys, and then they go away elsewhere and don’t even do research — they become doctors? What’s in it for us?

Some things are hard to learn by reading. Saul Sternberg, now a professor of psychology at Penn, once spent a quarter at Berkeley and was around when Stanford grad students and faculty in cognitive psychology came up to Berkeley to present their research. One of the grad students told Sternberg about a reaction-time experiment she had done about mental something or other (mental rotation?) in which the conditions compared varied in what the subject saw. Sternberg pointed out that it would be better to keep constant what the subject sees. This is the beginning of wisdom in the design of cognitive psychology experiments, but you won’t find it written down anywhere.

Four Great Modern Books (part 1: description)

Last week I read Send In The Idiots by Kamran Nazeer. It was so good — so fresh, clear, and moving — it made me wonder how it came to be. In other words, where do great books come from? Asking what several great books have in common should suggest answers to this question.

Among books published in the last 40-odd years these are the best I have read:

The Economy of Cities
(1969) by Jane Jacobs. Why and how cities grow or fail to grow. How new goods and services arise. They almost always begin in cities — the book starts with a discussion of how agriculture began. Cities and the Wealth of Nations (1984) by Jacobs is also great but too similar to Economy to be worth separate discussion.

Totto-Chan (1981) by Tetsuko Kuroyanagi. A memoir of the author’s primary school days at a progressive Tokyo private school. (Mentioned in The Shangri-La Diet.)

The Man Who Would Be Queen (2003) by J. Michael Bailey. What scientists, especially Bailey (a psychology professor at Northwestern University), have learned about the causes and effects of male homosexuality. One chapter is about male transsexuals, who are not always homosexual.

Send In The Idiots (2006) by Kamran Nazeer. The beautiful subtitle is Stories From the Other Side of Autism. When he was a child, Nazeer attended a school for autistic children. This book is about the adult lives of several of his classmates.

In later posts I will explain why I like these books so much and try to ferret out the secrets of their greatness.

How Well Does the Shangri-La Diet Work? (part 1: breakdown by starting weight)

The most basic question about the Shangri-La Diet is how well it works. As the host of The Amazing Race might say, there are many ways to answer this question, each with their own pros and cons. Thanks to Rey Arbolay, we can answer this question in a new way: by looking at the data in the Post Your Tracking Data Here section of the Shangri-La Diet forums, where more than 80 people have posted.

The goal of SLD, of course, is weight loss. The problem with just plotting pounds lost as a function of time on SLD is that a loss of 10 pounds is quite different to someone who starts at 120 pounds and someone who starts at 300 pounds. To deal with this I have divided the results by starting weight. In the graphs below, the ranges of weights were chosen so that there would be roughly the same number of people in each graph.

Starting weight makes a big difference — at least, between the two extremes. Many of the people who aren’t losing very fast are in the lowest quartile. There are still a few outliers — people at the higher starting weights who are losing slowly if at all — but not many.

The next step is to do an analysis that estimates the effect of starting weight and somehow removes it. It might be better to divide people by BMI rather than starting weight, and maybe the y axis can be improved.

Seymour Benzer (crippling the Salk Institute)

One of the most fascinating stories in Benzer’s oral history interview is about construction of the Salk Institute in La Jolla, California:

Benzer: Louis Kahn [the architect] asked Salk, “How much money have you got to put into the building?” And Salk said, “Ten million for endowment” — this was all from the commitment from the March of Dimes — “and a million dollars a year for operating expenses in perpetuity.” So Kahn went home and designed a building for $20 million. In fact, he bragged about this at some dinner he had in La Jolla. He talked about other buildings he had designed and he said it was always his policy to make the building for twice as much as the money available, because you could always count on the fact that people scurry around to find the extra money.

Salk went for that idea on the argument that later on it would cost much more to build it. That was absolutely true. But at the time it had the effect of liquidating the endowment. And everything suffered from then on. The institute . . . was always worrying about where the next buck was coming from.
. . .
Interviewer: So they liquidated their entire endowment to construct a more expensive building?

Benzer: Yes.

Kahn knew a general principal about human nature that I do not. Why do backers reliably “scurry around to find the extra money”? Something powerful is at work here.

Seymour Benzer (part 1)

I found a long interview with Seymour Benzer, a biologist at Caltech, who is one of my favorite scientists — lots of creative and important work. I was pleased to learn he is a foodie. During a 1956 trip to Japan he had sushi for the first time. “One of the greatest things about the trip,” he said in 1990 (when the interview took place), presaging a future in which every upscale American supermarket sells sushi. (For dinner tonight I made salmon tartare.) When I was a student at Caltech I knew the other students liked him, but I never met him.

Benzer began the use of fruit flies to study behavior. At Woods Hole I took a course called Neural Systems and Behavior with a fruit-fly segment taught by Laurie Tompkins. She had met Benzer at a party. When she told him she studied fruit-fly mating, Benzer asked if they have orgasms. Very early in his work on behavior, he gave a talk to Roger Sperry’s lab about his plans. After his talk there was a lot of debate about it. Some people thought it was very promising; others thought it was nonsense.

Interviewer: Why were people so skeptical?

Benzer: Why? A lack of imagination.

Excellent answer. I would have said: People are always skeptical.

Brain Food (part 9: supporting data, and a problem)

I reduced the amount of omega-3 in my diet. I stopped taking flax-seed oil capsules (I had been taking 10 1000-mg capsules/day) and started drinking extra light olive oil (2 tablespoons/day) instead of walnut oil. I made the change at midnight: Tuesday high, Wednesday low. The graph below shows measurements of my balance.

From Saturday through Tuesday, and preceding days, my intake of omega-3 was high; on Wednesday and Thursday it was low.

My balance was worse Wednesday morning than expected by extrapolation, which supports the idea I started with: omega-3 affects my balance. The time course of the change (the impairment was clear in hours) resembles the original observation: I could put on my shoes while standing much more easily the morning after the day I increased my omega-3 consumption.

But, as you can see, there was a problem: My balance rapidly improved during the low omega-3 condition. Although the results support my original idea, they don’t support it as strongly as they might. A comment on a previous post was “Aren’t you worried that your expectation of worse balance will skew the results?” No, I’m not I thought when I read it. I had several reasons for not worrying about the effect of expectations, and now another has come along: Surprising results, which imply that expectations have little effect. I did not expect significant improvement from practice. I had believed that because I balance everyday for hours while standing and walking, there would not be a large practice effect. I was wrong.

Psychologists don’t know much about motor learning. There are few well-established empirical generalizations about what makes motor learning faster or slower. Another gap in our knowledge is about the nature of the underlying change. When you get better with practice, how does your brain change?

After I shifted to low omega-3, I was surprised not only by how much I improved but also by how quickly. Was my improvement due simply to more tests? I plotted my scores versus test number:

This graph suggests that I improved more per test (greater slope) during the low-omega-3 condition than during the high-omega-3 condition. I think it is a spacing effect: During the low-omega-3 condition, I tested more often. During the high-omega-3 condition, I did 14 tests in 3.5 days — 4.0/day. During the low-omega-3 condition, I did 11 tests in 1.2 days — 9.1/day. I tested more often because I wanted to track the decrease. I think this difference in test rate is the reason for the slope difference. This effect is the opposite of the usual spacing effect in learning experiments, in which close-together (“massed”) practice is less effective than widely-spaced practice.

Relevant to the theme of inspiration via self-experiment, these results and my experience gave me several new (at least to me) ideas about motor learning. One was the existence of this spacing effect. Another was that practice changes the brain by increasing how much of the brain is devoted to the task. (The areas used for other tasks shrink.) Practice increases accuracy because more neurons become involved. The output, the action, is an average from a larger sample. One reason I thought of this is that after lots of practice, and I became quite accurate, the circular area on which I was balancing seemed larger. The notion that the brain area used by the task gets larger helps explain the spacing effect. Spacing is important because the brain doesn’t care how often you have done something in the distant past; what matters is how often you are doing it now. Thus the spacing effect helps make efficient use of scarce resources (neurons). The spacing effect occurs because neural activity causes an increase in something (call it X) that slowly fades away. If later activity happens while X is above a threshold, neural rewiring occurs.

The big practice effects and the idea that practice is more powerful when more frequent should interest anyone who wants to improve their balance (and probably other motor skills), from athletes to the elderly. In a simple cheap easy safe way I got better quickly–too quickly, actually. What happened reminds me of Little League: My batting got much better when I started swinging a bat in my backyard.

The lesson for my experimental design is that I should reduce and keep more constant how often I test.

Brain Food (part 8: a little more baseline)

As I mentioned earlier, while measuring my balance I’ve been listening to a book called Cod: The Fish that Changed the World. Around Hour 4 of the book I realized it was related to what I was doing: fish, brain food. Duh!

Each test of balance consists of 5 warmup trials followed by 15 regular trials. Each trial generates one number, a duration: how long I stand on one foot before the other foot touches the floor. It’s is a bit like surfing–balance, balance, balance, balance, balance, wipe out. (Surfers, skateboarders, skiers, snowboarders, gymnasts . . . this may interest you.) I enter the stopwatch times directly into my laptop. Each test lasts about 12 minutes. Because of the book, they’re pleasant.

I made several more baseline measurements of my balance with two changes:

1. To reduce fluctuations in the concentration of omega-3 in my brain, I did my best to take the flaxseed oil capsules as evenly spaced as possible. The general rule was to take 1 every 2.4 hours (= 10 per day). I didn’t take the capsules with me when I left home but I did follow that rule when I was home (not waking up to take them, however).

2. To make the distribution of (log) balance times more Gaussian (normal), I raised the maximum possible time from 30 seconds to 60 seconds. Previously I had stopped the test at 30 seconds; now the cutoff was 60 seconds. The problem was 30 seconds was too common — my balance was too good. Before the change, 3% of baseline measurements (6 out of 210) were 30 seconds. After the change, 12% of measurements (25 out of 210) were between 30 and 60 seconds and <1% (1 out of 210) were 60 seconds. The graph below shows results (mean & standard error) for 28 sessions.
The early problem (first 10 tests), discussed in my previous post, was that the means were fluctuating too much. A one-way ANOVA, with each test a different level, gave F(9, 140) = 2.6, p = 0.008. This is why I started trying to evenly distribute the flax capsules over the day. This seemed to work. For the last 18 tests, F(17, 252) = 1.0, p = 0.4. Unfortunately there is obviously an upward trend but that is okay because the change I am going to make — much less omega-3 — should if anything impair balance.

Brain Food (part 7: looking for a steady baseline)

Thanks a lot to those who commented on my previous post, very helpful comments. Barleyblair said that after greatly increasing her omega-3 intake she too found her balance greatly improved — not only could she put her socks on while standing she could put her shoes on while standing, which she hadn’t even dreamed of being able to do. Bekel said her sleep is deep and restful because of flaxseed oil. Pauls referred me to a Real-Age test of balance where you stand on one foot with your eyes closed. I tried it. It was way too easy: After two minute I opened my eyes and stopped the test. The table that tells you what the results means only goes up to 28 seconds. If the table is not completely bogus, then my balance is much better than average. Which is consistent with my working hypotheses that (a) the average American gets far too little omega-3 and (b) my brain function — indexed by my ability to balance — greatly improved when I increased my omega-3 intake. Keep in mind that according to conventional recommendations I ate plenty of fish (several servings per week) before increasing my omega-3 intake.

Before doing a simple test of the effects of omega-3 on my balance, I would like to establish a steady baseline and get an idea of what normal variation is. If possible, I would like to reduce normal variation — reduce background noise, in other words. With this goal I have measured my balance 13 times under roughly the same conditions: barefoot, listening to a book (a fascinating book, by the way: Cod: A Biography of the Fish that Changed the World by Mark Kurlansky) while doing the test, 20 trials per test. Each trial consists of standing on one foot on the cutting board on the 0.5-inch platform (see equipment here) and measuring how long until my other foot touches the ground. Each test takes about 10 minutes. I like the book so I enjoy the tests.
Below are the results from all 13 tests as a function of trial number. They show that there is a warmup period lasting 5 trials.

That just refines warmup measurements I posted previously. This is completely new:

The x axis shows when the test was done; points that are close together on the x axis were done close together in time — e.g., an hour apart. I hoped for a steady baseline so that I could go on to more interesting stuff. That is not what I found. I did a one-factor F test to see if there was significant heterogeniety. I used only the last 15 trials of each test, dropping the first 5 “warmup” trials. There were 13 levels (the 13 tests) of one factor. There was a highly reliable (p = .003) effect of test, meaning the variation from one test to the next was too large to be sampling error. And this test did not take into account the obvious clustering — tests close in time had similar results. The clustering makes it even more likely there were real differences in balancing ability from one test (or rather cluster of tests) to the next.

Apparently my balancing ability can change substantially in several hours! (For example, the time between the last test and the next-to-last test, the last in a cluster of three, was 7 hours.) And my test is sensitive enough to detect this! Forgive the exclamation marks. Nothing in my knowledge of psychology makes it obvious or even likely that this would be true — that a measure of quality of brain function would vary so much in hours that it could be detected by single measurements. Or that single measurements would be precise enough to detect such a change. Of course brain function (e.g., alertness) may get worse as you get sleepy but in this case my balance was much better in the evening than in the morning. The differences in my scores had no correlate that I could notice — I didn’t feel noticeably different when I did worse than when I did better.

What might be causing the differences? Body temperature or other circadian rhythm: Unlikely, because one would expect best performance when body temperature is highest, around 4 pm, which does not fit the results very well. More plausible: blood concentration of omega-3. It will be relatively low in the morning because while I was asleep I took no flaxseed oil or walnut oil. It will rise during the day as I consume these. This is consistent with the high measurements in the early evening.

Whatever the cause, these data suggest that something in ordinary life (which includes omega-3 consumption) can improve brain function within hours. If you, dear reader, know of other data that suggests this conclusion please let me know. Drugs and alcohol can quickly change brain function but they are not involved here. Nor am I listening to music, also believed to improve brain function (slightly). I am going to try to reduce fluctuations in omega-3 blood levels and see if I get more uniform measurements. I had a cup of tea with caffeine this afternoon; caffeine consumption is something else I will better control (by eliminating it).

Brain Food (part 6: a little more progress)

I did two balance experiments with a warmup of 8 trials. In one, the order of feet (which foot I stood on) was left, then right; in the other, right, then left. In both experiments I did much better (i.e., balanced longer) on my right foot than my left foot, ps < 0.001. This surprised me; I had never heard of such an asymmetry. The difference was so large that the platform size (0.75 inch) good for the left foot was too easy for the right foot. To make things as simple and easy as possible I decided to stop testing both feet and to only measure balancing on my right foot (and to use a 0.5-inch platform to make it more difficult and avoid a ceiling effect). I tested my balance (a) in silence and (b) listening to a book. The results were similar so I decided the standard condition will be listening to something. I want to make my balance test fast and pleasant. I came across several promising related facts: 1. On the Shangri-La Diet (SLD) forums, spacehoppa said she felt “solid on [her] feet” — which may mean her balance has improved. If so, the improved balance that I noticed may be widely true. She also said “my mind feels clearer,” another effect I noticed from omega-3’s, and more reason to think omega-3 improve brain function.

2. On the SLD forums, porkypine wrote, “I have a very strong reaction to the 1500 mg of OmegaBrite that I have begun taking in the morning. . . . During the day, I am not just happier, but actually chipper, which is not a normal state for me. I have wondered if I am getting too much Omega-3.” This supports one of the assumptions behind my upcoming tests of the effects of omega-3 on balance: the effects of omega-3 on the brain happen quickly. It also highlights an advantage of measuring balance rather than something else, such as mood — namely, it is reasonable to assume that the better your balance, the better your brain is working. As this quote shows, the mapping between mood and goodness of functioning is not so clear.

3. In a book about neurology (Defending the Cavewoman by Harold Klawans), including Creutzfeldt-Jacob disease, I read: “A [Fore] woman in late pregnancy who was unable to walk easily across a narrow tree trunk bridging a gorge knew from that change in her balance that she had kuru and that she would die of it. The physicians examined her and thought she was normal, but in less than one year, she was dead.” This shows that balance is an especially sensitive measure of brain function, at least under demanding conditions. It’s relatively easy to notice worse balance.

Balance is also much easier to quantify than many other measures of brain function, such as mental clarity.