Break Through Your Set Point

HarperCollins Publishers, Inc.

Chapter One

The Science of the Set Point

It is one of the great wonders of the brain that body weight stays remarkably fixed (as a "set-point") most of the time in most people.
—Christian Broberger, M.D., Ph.D.,
Department of Neuroscience,
Karolinska Institute, Stockholm, Sweden

The drive to regain is mainly in the brain.
—Barry E. Levin, M.D.,
professor of neuroscience,
New Jersey Medical School,
East Orange, New Jersey

What is a set point?

Your body weight set point is the number on the scale your weight normally hovers around, give or take a few pounds. Your heredity and your environment—starting back at the moment of your conception—determine your set point. Most people's set point is "set" around age 18. Before that age, your body is still growing, and you need to eat more calories than you burn to encourage growth and development. Girls may reach their set point a little before age 18, and boys may reach theirs a bit later. But soon after you stop growing in height, your body weight tends to settle at a fairly stable number.

Your set point doesn't necessarily remain the same throughout your lifetime. Few of us weigh the same as we did when we finished high school, and that's perfectly normal. As you age, your metabolism slows down a bit, which is why most people put on a few pounds. Additionally, women normally gain about 25 to 35 pounds during pregnancy. If they don't lose most of that extra weight within about a year of giving birth, they're likely to raise their set point, especially if that trend continues during future pregnancies.

Gaining just under a pound or so per year from about age 20 to age 50 is common and not necessarily bad for your health. People get into trouble when they gain more pounds more quickly, ending up at an unhealthy body weight. Over the long term, excess food and insufficient exercise will override your body's natural tendency to stay at its set point and lead to a higher, less healthy set point.

What's My Silhouette?

In addition to a body-weight set point, everyone has a silhouette that closely parallels their body shape. A chart developed in the early 1980s depicts a range of body sizes, from slender to obese. Used as a research tool to examine people's perceptions of their own body image (both actual and desired), the silhouettes provide a close approximation of a person's body weight. In effect, your silhouette is a visual representation of your set point.

I will use eight of these images for each gender as a simple way to help you see how you can change your silhouette to a healthier profile by resetting your set point. Take a close look at these silhouettes and circle the one that most closely resembles your body now. What about your silhouette at age 18? (Note that these silhouettes were developed using Caucasians, so they may not accurately depict your body if you have a different racial background. But overall they provide a close approximation for most people).

Easy Come, Not-So-Easy Go?

Researchers who study weight control have discovered that people who gain weight easily find it hard to lose extra weight, but people who struggle to gain weight find it easy to lose excess weight. A slow, gradual weight gain will fool your body into thinking that your set point should be higher—and, in fact, that does reset your set point. For instance, a 20-pound weight gain over several decades moves you from silhouette 2 to 4. Then when you try to lose weight, your body defends that higher weight, making weight loss more difficult. On the flip side, a rapid, short-term weight gain doesn't fool your body and therefore does not reset your set point. Your body will work to defend its lower, normal set point, and shedding those excess pounds will be relatively easy.

But just as it's possible to reset your set point to a higher point, it's also possible to lower it. The secret is to work with, not against, your body's natural tendencies and lose weight slowly, one silhouette at a time.

How your body sets your set point

To appreciate how your body works to maintain your weight, it helps to understand a little bit about the internal controls that govern this complex process. These controls include a tiny structure deep within the brain, nerves that run between the brain and the stomach, and a host of hormones. Central to this entire system is your metabolic rate, which automatically adjusts in an effort to maintain your set point. (But, as you'll learn later, external forces can override these internal controls.)

Making Sense of Metabolism

Metabolism refers to the basic chemical processes within the body that keep you alive. It's also vital to understanding weight control. During the periods of the day when you are not eating, proteins, carbohydrates, and fats are broken down into their building blocks, creating energy to fuel all your body's functions, while other processes consume these substances. Your metabolic rate is a measure of how fast your body uses that energy, or burns calories, when you're at rest, just lying quietly and not doing anything. Also known as your resting energy expenditure (REE), this number accounts for about 70% of the calories you burn each day. On average, this comes out to about 10 calories per pound of body weight.

REE varies from person to person and changes throughout life. It is mainly influenced by several things you can't control: your genes, your age, and your sex. Your energy metabolism slows down as you age, a natural consequence of the body's cells wearing out and not functioning quite as efficiently. Men tend to have a slightly higher metabolic rate than women, although a woman's will (not surprisingly) rise temporarily during pregnancy.

Excerpted from Break Through Your Set Pointby George Blackburn Copyright © 2008 by George Blackburn. Excerpted by permission.
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