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?

Easy Come, Not-So-Easy Go?

HOW YOUR BODY SETS YOUR SET POINT

Making Sense of Metabolism

The Internal Speedometer

The Thyroid Connection

The Hypothalamus: Headquarters of the Set Point

The Autonomic Nervous System

Sending Signals: A Host of Hormones

The Sensing Stomach

Obesity as a Metabolic Disease

WATCHING THE SET POINT AT WORK

The Framingham Heart Study

The Minnesota Starvation Study

The Vermont Prison Overfeeding Study

Movie Stars

External Forces Trump Inner Balance

Source: George L. Blackburn, M.D., Ph.D., "Break Through Your Set Point: How to Finally Lose the Weight You Want and Keep It Off," 2008