Author: Seth Roberts

Does Walking By McDonald’s Make You Fat?

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Few people have used the theory behind the Shangri-La Diet more successfully than Tim Beneke, an Oakland journalist. I put before and after photos of him — before and after he lost about 100 pounds — on the front page of the proposal for The Shangri-La Diet. He writes:

It’s very clear to me this summer that it’s much easier for me to go tasteless and only consume the mush if I don’t go to Berkeley, and just stay home in my apartment (except going for my neighborhood walk). And it’s not merely a matter of behavior. When I go to Berkeley and walk near places where I am accustomed to eating (and tasting) — mostly restaurants, sandwich shops and coffee houses — I actually experience more hunger and must consume more mush to satisfy hunger than if I stay home.

I’m not surprised that auditory and visual signals for food cause hunger. There are lots of conditioned cravings like that. Tim goes on to wonder if these learned signals for food raise the body-fat setpoint, as the theory behind the Shangri-La Diet says that food-associated flavors do. If you walk by your favorite bakery every day, will you weigh more than if you don’t?

I always lose weight when I travel in foreign countries. I’ve attributed this to unfamiliar food. But could unfamiliar places also play a role?

In 1973, Edward Zamble, a professor of psychology at Queen’s University, Kingston, Ontario, published an experiment very relevant to this question. He divided rats into two groups. Both group got their daily meal at random times. For one group, the meal was preceded by 30 minutes of light; the light went off before the food was available. The other group was exposed to the same amount of light but the light bore no relation to when they were fed. The rats with signaled food ate more and weighed more than the rats with unsignaled food.

I knew of this experiment — and often mentioned it — before I came up with the theory behind the Shangri-La Diet, but I never connected them. Thanks, Tim.

Science in Action: Omega-3 (time course 2, with eggs)

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Last week, I tried to measure again the time course of flaxseed oil’s effect on how well my brain works. As before, I used a letter-counting test. The test consists of trials where I see a four-letter display such as ECQZ and type as quickly as possible how many letters from ABCD are among them (in this case, 1). 200 trials per test, about one test per hour.

On Tuesday, about 3 pm, I drank 4 tablespoons of flaxseed oil. Here’s what happened:

graph of flaxseed oil results

The flaxseed oil seemed to reduce reaction time. The maximum reduction was 40 milliseconds, which happened 2-3 hours after drinking the oil. The effect was gone about 6 hours after drinking it.

The next day I expected my scores to be close to the pre-drink baseline. At 5 pm my score was much lower than expected. The difference from baseline was close to the effect of flaxseed oil; moreover, it disappeared at close to the same speed as the flaxseed-oil effect disappeared.

Although surprising, this had a plausible explanation: About three hours earlier, I had eaten three eggs from grass-fed (also called range-fed) chickens. (More precisely, I had had one egg in a smoothie at 11 am and two scrambled eggs at 2 pm.) Such eggs are believed to be high in omega-3. A 1992 paper compared the amount of omega-3 in supermarket eggs and eggs from a Greek farm, where the chickens ate “fresh green grass leaves and wild plants including purslane . . . fresh and dry figs, barley flour . . . insects of all kinds.” The supermarket eggs had little omega-3; the Greek eggs 10 times more.

My eggs came from the Bay Area Meat CSA, run by Tamar Adler (tamareadler a/t earthlink.net), a chef at Chez Panisse, who is looking for new members. Pickups in Berkeley and San Francisco.

Jane Jacobs and Traffic Tickets

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Rexford Township, Michigan, has started to pay police officers according to the number of tickets they write. In Systems of Survival, a book about moral systems, Jane Jacobs criticized something similar: ticket quotas for police. Treating guardians (such as police) as if they were in commerce doesn’t work well, she wrote. There are two ways of making a living (taking and trading). Both have value, but they need to follow different rules of conduct (which we may grandly call morals) to work well.

What Goes Around Comes Around

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One of my favorite stories in Discover Your Inner Economist by Tyler Cowen:

During one riot in Michigan, one woman sold stones to rioters. . . . Small stones went for $1, larger stones brought in $5 a piece. Most of the rocks were thrown at police. . . . The woman claimed that she collected about $70 from her efforts, but she stopped when she was hit by a rock herself.

A perfect illustration of the title of this post.

What makes a good story? Perhaps 1. Hero. 2. Villain. 3. Struggle. 4. Details. 5. Humor. 6. Message. 7. Goodness is rewarded or sin is punished. 8. Truth (it actually happened). The rock story has six of these.

Nutritional Psychology: A Gaping Hole Where a Field Should Be

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Yesterday I attended the annual convention of the American Psychological Association (APA) in San Francisco. I was also measuring (again) the time course of omega-3 effects. The exhibits hall was full of books. I picked up three introductory psychology texts to see what they said about nutrition. None of their indexes listed nutrition; apparently they said nothing about it. None of the hundreds of books I saw was about nutrition — that is, about how to nourish the brain. Yet the APA is mainly about mental health.

It’s not just APA. At Berkeley, I’ve attended dozens of talks in the Nutrition Department. I have never seen another psych professor or grad student at any of them. Nor have I seen a nutrition professor at any Psychology Department talk. Both disciplines have Annual Review series. In last seven years, there hasn’t been a single article in the Nutrition series about behavior or cognition (aside from eating) nor a single article in the Psychology series about nutrition (aside from an article about weight control).

Sometimes interdisciplinary is hard. Cognitive science has tried to unite computer scientists with linguists and philosophers and psychologists. That’s hard because computer scientists are engineers, not scientists, and philosophers are neither. But nutrition and psychology are both experimental sciences. Nutrition is an independent variable (food), psychology a dependent variable (behavior). They naturally go together, especially if you are concerned with mental health.

Now and then someone will study how Disorder X responds to Nutritional Treatment Y — how depression responds to omega-3, for example. Better than nothing, absolutely, but not the best approach. By the time something is broken it is likely to be (a) a mess and therefore hard to measure and (b) hard to put back together. If you want to learn how a car works, should you study a car that works or a car that doesn’t work? The answer isn’t obvious, at least to cognitive psychologists, because for half a century they mainly studied how memory, perception, etc., failed. In the 1960s, Saul Sternberg taught the rest of the profession a better approach — namely, study a car that works. Sternberg made popular the kinds of experiments usually done today: reaction time experiments with easy problems that subjects almost always get right. My omega-3 research has illustrated the truth of Sternberg’s general point. I found much clearer effects of flaxseed oil on easy tasks (easy arithmetic, an easy memory task) than on a difficult task (digit span). A better way to learn how food affects our brains will be to study the effect of food on healthy brains. Such experiments will be much much easier than studying people who are depressed, children with ADD, schizophrenics, autistic children, drug addicts, and so on. I’m sure that the conclusions from healthy brains will generalize to malfunctioning brains, just as all cars — working or broken — work the same way.

Even in Sweden

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From the SLD forums, someone who recently started SLD:

On vacation at my friend’s place in Dalarna Sweden. Used to live here some years ago and I´m now hanging out with all my old buddies, an jeeees… everything’s about food. BBQ´s, breakfast, snacks and lunch….? What´s this? Has food been so important before? Haven´t noticed that before, all food talk and all snacking. For fun I counted how often the word FOOD was used-25 times- during the day!!!

Why Does Gum Disease Correlate With Heart Disease?

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People who have heart disease are more likely to have gum problems. Why? According to an online health magazine from the University of Texas,

Medical researchers have two main theories to explain the link between gum disease and heart disease . . . One theory is that the bacteria from periodontal disease enter the blood stream and stick to the blood vessels, creating a thickening of the walls, which may end up clogging these vessels. The second theory is that the chemical by-products from gum disease cause the same clogging effect. The chemicals may come from the by-products of the bacteria or from the chemicals produced by the body’s own immune system.

A third possibility, not mentioned in the article, is that both gum disease and heart disease are caused by too much inflammation.

The three cases I described yesterday, in which high-omega-3 oils rapidly eliminated gum disease, convince me that the third possibility is correct. When you take 2 tablespoons/day flaxseed oil or 1 teaspoon/day fish oil, you are not killing the bacteria in your mouth. The bacteria remain as plentiful as ever. The difference is that your body is no longer overreacting to them. Plenty of evidence suggests that heart disease is caused by too much inflammation. This correlation is more evidence.

Why omega-3s reduce inflammation is known. The body requires omega-3 to build an anti-inflammatory signaling molecule. Not enough omega-3, not enough of this molecule, too much inflammation.

Ortho-Ergonomics

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In honor of this week’s BMJ cover story.

BMJ cover

My current test to study omega-3s (letter counting)nvolves lots of typing. To avoid carpal tunnel syndrome, which I started to approach a few weeks ago, I use one hand to raise the other one, as these pictures show.

how I do letter-counting test: view from left
how I do letter-counting test: view from right

Since I started doing this, I haven’t had any problems. No discomfort. I usually put an hour or more between tests. (Each test involves 200 keystrokes — 50/finger — in a few minutes.)