I’ve struggled a bit with my weight over the years. I try to keep my BMI around 25, but if I don’t watch what I eat it tends to creep upwards towards 27 and even 28 before I even notice. Hence I’m always looking for new techniques to control my diet. This morning I came across an on-line book called The Hacker’s Diet. Written by John Walker, the founder of Autodesk, Inc., it’s a geeky, data-driven approach to maintaining your weight.
I liked this book right away, because Walker seems to have come to some of the same conclusions I’ve reached over the years. First of all, what you eat makes little difference to your body. Whole wheat, organic, natural, vegetarian, high carb, low carb, raw, Paleolithic or Neolithic, it doesn’t matter. Human beings are omnivores, and we can thrive on almost anything. Weight control is all about calories, and to lose weight you have to eat fewer of them. As an aside, take look at this article about a guy who lost 27 pounds on a diet of Twinkies and Doritos.
I’ve also come to the conclusion that while exercise is great for maintaining health, it has little effect on your weight. The book makes this clear: there just aren’t enough hours in the day to perform enough exercise for it to have a significant effect on your weight. Walking for an hour burns as many calories as there are in a single donut. So why not just skip the donut?
Not long ago (see this post), I came to the conclusion that dieting is a matter of weight, not calories. I still think there’s something to this idea — after all, there’s nothing relativistic happening in our bodies, so the principle of conservation of mass has to hold — but The Hacker’s Diet, and this figure showed me that the situation is a bit more complicated. The intake and excretion of water has too great an effect on the mass balance. As Walker writes:
On a day to day basis, the water you consume, whether directly in beverages or as part of the foods you eat, and the water you excrete in your various excursions to the hydraulic accommodations, dwarfs the weight of the food you eat and the solid waste you dispose of … Most of the changes in weight you see have nothing to do with how many calories you’re eating or burning. Instead, all you’re seeing is how many pounds of water happen to be inside (your body) at the moment.
In addition, foods vary greatly in the amount of water they contain, so you can’t focus strictly on the mass of what you’re eating.
As far as I can tell — and I haven’t read all the way through yet — the diet depends on calorie counting and daily tracking of weight, coupled with exponential smoothing to even out the daily variations. It looks very promising.