Seizing control

Understanding how a system works is the first step in controlling it. Thinking of yourself as a rubber bag may not be glamorous, but it casts the realities of weight control in stark contrast, dispelling the myths and misconceptions that collect around the subject. Compared to most systems engineers design, this one is pretty simple. Let's look at how to control it.

The first step is identifying what we want to control. Well, that's obvious: the goal is control our weight. Our weight is just the contents of the rubber bag.

So, what are the inputs to the system? Again, simple. There's only one input: how much we eat, measured in calories per day.

What are the outputs from the system? Almost as simple: how much we burn, again measured in calories per day, and what comes out. But since what comes out is for all intents and purposes simply the discarded waste products from processing what's been eaten and, in any case isn't subject to control, we can ignore it.

Thus we've simplified the rubber bag even further, to the following system:

Now we're getting somewhere! Calories in--calories out: both readily calculated. You get calories in by adding up the calories of everything you eat in a day: good old ``calorie counting.'' Calories out, the calories you burn in a day, can be initially estimated based on your sex, height, and frame size using the tables on pages and . Later, you'll be able to refine this estimate as you monitor your weight.

To determine whether you'll gain or lose weight--whether the rubber bag will grow or shrink--just take the number of calories in, what you eat, and subtract the number of calories you burn. If the number's positive, you're eating too much and the excess calories will stay in the bag; you'll gain weight. If the result is negative, you're burning more calories than you're putting in; the bag will shrink as the reserves stored in fat cells are drawn down to meet the body's energy needs; you'll lose weight.

  To complete our understanding of the rubber bag, we need but one more fact: a number that relates an excess or shortfall in calories to pounds on the scale. That's given by the number of calories of energy stored in a pound of fat: about 3500 calories per pound. (Fat is really remarkable stuff when you think about it from the standpoint of biochemistry rather than belt size. Life has discovered, in fat, an extremely compact and efficient way to store energy. We often think of sugar as ``pure calories,'' but a cup of sugar contains only 750 calories. A cup of lard, essentially pure fat, contains more than 1800 calories, almost two and a half times the content of sugar. Is it any wonder flaky pie crust is purgatory in a pan for anybody with a weight problem?)

If, over a period of time, the calories in the food you eat exceed the calories you burn by 3500, you'll put on about a pound. Conversely, if you reduce your food intake so that you burn 3500 calories more than you eat, you'll lose about a pound.

Please reread that last paragraph. It contains essentially everything there is to know about weight control. All the rest are tools, techniques, and details, important ones to be sure, but useless unless you first understand the system. Any tools that achieve the same end, balancing the calories you eat against the calories you burn, will have the same results. (You can dig a ditch with a pointed stick, a shovel, or a backhoe. The result is the same, but you can get the job done faster and with less effort by using the best tool. Still, don't confuse the shovel (the means) with the ditch (the objective), as most diet books tend to.)

Note the phrase ``over a period of time,'' in connection with a calorie excess or deficit. One single event: eating a half gallon of ice cream by yourself, right from the box, at one sitting, or going 36 hours without eating as you drive the Cannonball, doesn't have the impact of a consistent calorie excess or deficiency over an extended period of time.

Once you understand these simple facts, the realities of weight control can be reduced to calculations you work out in your head or on the back of a napkin (a particularly appropriate place for them!). Assume you're male, 5'11'' barefoot, with an average build. You burn in the vicinity of 2200 calories a day. As long as you eat about that much every day, your weight will stay the same.

Suppose you start putting in an extra 250 calories a day. That sounds like a lot, but consider the following:

These little compensations for life's vicissitudes can add up. Indeed they do...to the tune of an extra 1750 calories per week based on a daily excess of 250 calories (250x7=1750). The weekly surplus of 1750 calories equals half the calories in a pound of fat (3500/2=1750). As week gives way to week, you'll find you're gaining about half a pound a week. Two pounds per month. About 25 pounds a year, by which time none of your clothes will fit, you'll look awful, be depressed about the situation, and feel unable to get a handle on it unless you've grasped the simple arithmetic at the heart of the problem.

But consider the flip side of this calculation. Passing by any of the treats listed above, or its equivalent in other foods, hardly constitutes starvation or survival rations. And yet, simply by eating that little bit less every day for a year, you can subtract 25 pounds from your weight in the space of a single year (assuming you weren't gaining weight before).

We'll look at these kinds of calculations in more detail when it comes planning your weight loss, but first let's consider the two sides of the rubber bag, what you eat and what you burn, from the standpoint of the control you can exert over them.

• Controlling what you burn
• Controlling what goes in