On the 17th day in the month of September, 2008: I started dieting.
I had discovered The Hackers Diet and reading it finally turned the key that allowed me to truly understand how weight loss and weight gain work. Armed with this knowledge I was able to almost immediately rocket down the pounds, and keep them off.
The Hacker’s Diet is an online book written by one John Walker who, as an engineer, decided to approach weight loss as an engineering problem.
So, there was nothing for it but to shed all those pounds I’d packed on through the stressful years of starting, growing, and running a company. “If all you have is a hammer, everything looks like a nail.” I’m an engineer. I decided to approach weight loss as an engineering problem.
I studied the human body the way I’d tackle a misbehaving electronic circuit or computer program: develop a model of how it works, identify the controls that affect it, and finally adjust those controls to set things aright.
It worked! In less than a year, totally under my own direction and without any drugs or gimmicks, I went from 215 pounds to 145 and achieved physical fitness. Since then, I’ve kept my weight right where I want it with none of the yoyo swings I’d suffered in the past. All of this was accomplished in less than 15 minutes a day, and without any significant changes in the way I choose to live my life.
- John Walker, The Hacker’s Diet : Introduction
His thesis is that eating for weight loss is actually extremely simple: only calories matter. Eating to be healthy and to not feel sluggish or lethargic is an entirely different matter. The two are related of course, but independent of each other.
You could actually lose weight if you just ate candy bars, you’d just feel miserable doing it because you wouldn’t be getting the vitamins and minerals you need and, the calories would be packed into small sizes and leave you feeling hungry all the time. 240 calories of spinach is much more filling than 240 calories of Butterfinger. Likewise, you could actually gain weight eating healthy foods; you’d just have to eat enough of them.
At its simplest (from the perspective of weight loss) the body is just a calorie burning machine. Every day it burns a slightly flexible number of calories (that flexibility is metabolism) to keep itself warm, functioning, and without adding or burning to its energy stores (fat). Eat so much that it can’t burn all the calories and they get stored; eat so little that it can’t meet its energy requirements and stored energy is burned. Simple!
Before reading this, I had a very skewed understanding of how dieting worked. I thought that weight was a simple result of the number of calories eaten per day. Eat X number of calories per day: weigh Y. But that isn’t so. Maintaining a constant weight just means eating within the range of daily calories that your body can take in without having to alter its energy stores. So, assuming my weight was currently constant, all I needed to do was temporarily reduce the number of calories in, wait for my body to burn off enough energy stores, then resume my regular eating.
So I did, and it worked. In three months I lost over thirty pounds. I can, in fact, set my weight goal to any arbitrary number (within reason) and weigh that amount. During the loss I experimented with different types of foods: high fructose corn syrup, carbohydrates, etc. None altered in any way the downward slope of my weight, only calories. Avoiding carbohydrates was helpful though as they are very calorie dense foods.
Now, you may ask, what about exercise? Can’t I just exercise more and lose weight that way? Well, yes; but no.
Don’t kid yourself into thinking that exercise, by itself, will make you lose weight. Consider the following activities, and the number of calories an average person burns per hour in each.
| Activity |
Calories/hour |
| Walking |
300 |
| Bicycling |
300 |
| Aerobics |
400 |
| Swimming |
400 |
| Tennis |
500 |
| Basketball |
500 |
| Jogging |
700 |
Compare those numbers, remembering that they’re for a full hour spent nonstop in the exercise, with the calories in the following food items:
| Tasty Treat |
Calories |
| Peanut butter sandwich |
275 |
| Pizza (3 slices) |
500 |
| Big Mac |
560 |
Clearly, even an hour a day of exercise doesn’t account for much food. And what’s the likelihood you’ll find the time to spend a full hour, every day, month after month, year after year, doing those exercises?
So, don’t exercise to try to burn off calories and lose weight. Unless you’re a professional athlete or obsessed with sports, you’re not likely to spend enough time exercising strenuously enough to make much of a difference. Exercise will help you lose weight in more subtle ways. Regular exercise increases your rate of metabolism: the number of calories you burn all the time. Plus, for many people, exercise actually reduces appetite.
- John Walker, The Hacker’s Diet : What, Me Exercise?
So, yes, exercise is great but it’s not the key to easy, consistent weight loss. You exercise to live longer and feel better, not to take off the pounds.
Even if you don’t buy into any of this Hacker’s Diet stuff, I’d still like to point you to the weight tracking tool created for The Hacker’s Diet. It treats each daily weight as a data point for a exponentially smoothed weighted moving average.
When faced with apparently random variation in a collection of things, the first thing a statistician does is compute an average or, more precisely, the arithmetic mean. What’s the average height of 30 year old men? Measure a whole bunch of them, add up their heights, and divide by the number you measured. Whether the number you get is useful for anything is another matter, but at least you can always easily calculate an average.
…
… Averaging has filtered out the influence of the daily variations, leaving only the longer term trend. But we can do even better. Rather than waiting for ten days to elapse before computing the average, why not each day calculate the average of the last ten days? This will give us a continuous graph rather than just one box every ten days, and we don’t have to wait 10 days for the next average.
- John Walker, The Hacker’s Diet : Signal and Noise
Given your daily weight measurements, the HDO weight tracker will smooth out the variations (being bags of mostly water, we tend to slosh a bit) to yield an accurate reading of your current weight, as well as your trend. (If you’re interesting in the actual math – The Hacker’s Diet : Pencil and Paper)
This is an extremely powerful tool because it helps detect changes in weight trend (up or down) before you actually really notice the shift in numbers on the scale. Speaking from experience here, when I stopped tracking my daily weight I quickly shifted from “I weigh 192.7 lbs.” to “Eh, I weigh something like 195 to 200.” This sort of nebulous measuring reduces the granularity of weight tracking from pounds to tens of pounds and can allow the weight to sneak back in.
The Hacker’s Diet is the meta-diet from which all other dieting and weight loss systems descend. It allowed me to truly understand how calories work, how metabolisms work, and how weight is controlled by their simple function.
Calories In – (Calories Out + Calories Burned) = Weight Loss or Gain
