The Hacker's Diet

"The Hacker's Diet" is a book written by John Walker (yeah, the Autodesk guy). Originally published in 1991, the book is now available online at http://www.fourmilab.to/hackdiet/.

Walker's weight-loss plan (subtitle: "How to Lose Weight and Hair Through Stress and Poor Nutrition") compresses the functions of the human body into what he calls the rubber bag. Stuff more food in, and the bag stretches; put in less food, and the bag shrinks.

Walker, as an engineer, took an engineer's approach to being overweight: What does the system take as inputs and outputs? What can we adjust to get the desired result? In this case, how do we do that?

The body's inputs are, basically, foods and more foods. The system can be adjusted by controlling the quantity (and, to a lesser degree, quality) of food eaten, and by tweaking the rate calories are burned from the system (i.e. exercise). Walker says that either component of the system can be adjusted to some benefit, though the system works better as a whole than as discrete components.

The plan apparently worked well enough for him: He claims to have lost 70 pounds in a year, and that he hasn't regained any of that weight. The system takes just fifteen minutes a day, and doesn't require any drastic changes of lifestyle.

This book is just plain funny, and disturbingly insightful. Maybe it's because I'm a geek, so I know where the author is coming from, but I found it eminently readable. Heck, I read it a few months back (when I was in my "I'm fat, so fucking what?" phase) and thought it was funny then too.

Yeah, I know, there's not much to this node yet. I plan to give the whole thing a while, inspired by the second writeup for Uberman's Sleep Schedule, and add to this node in a while.

Reference: The Hacker's Diet (dude. The URL is up there. No, really.)

I've just read the book, and I found it a good read. However, Walker has neglected an important factor in his models, at least as far as appetite control goes: time delay.

Imagine the house analogy from the book. Only, this time, we have the heater/air conditioner (let's call it a heat pump, with the ability to pump both ways) in one room, the room you want to control the heat in, and the thermometer that affects the feedback in another. Let us examine how this system works now.

Let us first assume that the heat is uniformely spread throughout the house. Both rooms will after a certain amount of time during which the heat pump is not working, be at the same temperature, and fall and sink at the same rate. This is the state we have our system in when we start off.

Now, the temperature drops below our minimum. The thermometer registers this, and sends a message to the heat pump to start negative feedback. The room with the heat pump is quickly brought back up above he minimum temperature. The room with the thermometer, however, is still colder. So the heat pump continues heating. And then, finally, the thermometer measures a temperature above minimum, and turns the heat pump off.

By now, however, the room with the heat pump is far above the preferred temperature.

The same happens in our bodies. We eat, and the food is processed. The body, once it has processed enough of it to see that it has gotten the energy it wants, tells you that you are full, that you don't need to eat anymore. Of course, by the time this happens, you've already eaten an amount of food that hasn't been processed yet. Depending on how fast you eat, this amount can vary from negligible to obesity.

So many of us don't actually have an Eat Watch that is wired wrong, but rather one that is set too slow. See now why it's actually a good idea to eat slowly?

It's also probably worth mentioning that it seems like one can actually rewire one's Eat Watch. Though that's something I won't go into.