The title is somewhat misleading, since the book covers many other aspects of weight loss. Many of them useful, but the connection with how to overcome your set point was not clear. Researchers first came up with the "set point" theory in 1982. They found that many biomechanisms in the body act as a sort of weight thermostat. If you suddenly eat a lot and start to gain, these mechanisms kick in to help you lose the extra weight.

Cut way down on your calories and start a heavy exercise program, and your body slows down to avoid losing too much weight. This accounts for the tendency of dieters to hit a plateau after they've started a weight and exercise program and lost about 10% of their pounds. After the excitement of the first month or so, to suddenly stop losing weight despite all your efforts can be immensely frustrating, and accounts for many dieters quitting before they attain their goals.

Many experts emphasize the genetic nature of the set point, but although genetics is one factor, it's obviously not the only one. The set point can and does change. Most of us gradually gain weight over the years. If the set point didn't change, we'd remain our 21 year old weight while eating whatever we pleased. If only. Plus, we know that people can continue to lose weight despite the set point. People fed starvation diets in concentration camps for a long period continue to waste away.

An important point Dr. Blackburn makes -- and which more people seeking permanent weight gain need to understand -- is that changing the set point takes around six months. Lose that easy 10% of excess pounds, he advises, then continue your weight loss program but don't expect any more progress for another six months. After that, your set point has been reset to your 90% weight, and you can then easily lose 10% of that. Unfortunately, at that point the book continues with lots of advice for dieters. Much of it is good, but little is new. But he didn't clearly draw the lines. Is it following his advice that resets the set point to a lower level? Or just waiting six months? Plus, he is clearly of the calories-are-weight school. He dismisses the Zone health plan as just a "fad diet" without bothering to address any of the medical issues Dr. Barry Sears writes about.

He does not even address the glycemic index. Dieters are told to eat baby carrots even though carrots have a high glycemic index, meaning that they raise your insulin almost as much as table sugar. When he writes about exercise he's just as shallow. He treats all forms of exercise as just a way to burn calories, even though researchers have determined that the real benefit lies in how high intensity exercise can alter your metabolism for up to forty-eight hours after the exercise. And how it can increase your supply of human growth hormone and, if you're a man, testosterone.

Those metabolic and hormonal changes are far more important for both losing weight and general good health than the calories you burn while walking on a treadmill. Dr. Blackburn ignores them all. Instead, he advises you to move more -- even if just tapping your fingers to burn calories. This advice to burn more calories by acting jittery and nervous seems to contradict the later sections in the book which advise dieters to reduce stress.

This, and his stress on the importance of getting plenty of sleep, is welcome and useful. He's correct that not enough diet books stress the importance of reducing or dealing with stress in healthy ways rather than overeating. I searched Amazon and didn't find any other points in print on the set point, so apparently it is filling a gap in the marketplace. However, people who want long term health, especially when they need to lose weight to get there, should keep the set point in mind while they're on the Zone diet, doing high intensity sprints several times a week and body weight exercises on other days of the week.

Remember that your body interprets a fast 10% weight loss as the beginning of a famine. Stick to eating in the Zone and exercising regularly. After six months your body will figure out that you haven't starved to death, and reset the set point down. Then keep going. Short term dieting is not healthy. Proper eating and exercise throughout your life is what will keep you slim and fit.