The weight that a person’s body naturally tends to maintain. Understanding how the metabolic set point works can help people both understand why weight loss is so difficult and achieve long-term weight loss.
The part of the brain called the hypothalamus helps keep the body in balance in several ways, including maintaining a stable weight: It controls hunger, body temperature, and the amount of sugar, salt, water, and other substances that are retained in the bloodstream. The hypothalamus uses a number of hormones to control and maintain the body’s weight set point.
The set point theory was developed in 1982 to explain why repeated dieting rarely results in long-term weight loss. Instead, people tend to lose weight and then regain it and possibly more. However, some researchers believe that it is possible for a person to change his set point and keep off lost weight. One possibility is that increased exercise can lower the set point. Among the thousands of people enrolled in the National Weight Control Registry — a registry of people who have lost at least 30 pounds and have maintained that loss for one year or longer — 94% increased their physical activity as part of their plan to lose weight and keep it off.
In his book Break Through Your Set Point: How to Finally Lose the Weight You Want and Keep It Off, George Blackburn, MD, PhD, Associate Director of the Division of Nutrition at Harvard Medical School in Boston, Massachusetts, offers a plan for resetting the metabolic set point that includes physical activity and also dietary changes. He observes — as others have — that after a person loses about 10% of his body weight, his body starts burning fewer calories to protect itself against starvation, and weight loss slows or stops. However, Blackburn believes that if this 10% lower weight can be maintained for six months, with no weight regain, the body’s set point will effectively be reset, and more weight can be lost, if desired.
Blackburn emphasizes that weight must be lost slowly to reset the set point; fast weight loss tends to result in fast weight regain. (Similarly, gradual weight gain over the years resets the set point upward, while fast weight gain does not.) To ensure that weight loss is gradual, Blackburn recommends cutting daily calorie intake only by 10% until 10% of initial weight is lost — a process that may take anywhere from six months to over a year. He also recommends choosing nutritious foods, eating slowly, and being physically active for improved health.