There are many books that teach us how to lose weight. Examples are the Atkins Diet, the South Beach Diet, the Zone Diet, the Cabbage Soup Diet and the Drinking Man’s Diet. All of these diets work. If you do as the book instructs you will lose weight.
The problem is that your goal is not merely to lose weight, but to keep it off after the diet is over. Keeping the weight off is the hard part. Most people who lose weight regain some or all of it within a few years. There’s a simple reason why this happens.
In this book we will meet several people, all of them fictional. One of them is Kay, a middle aged woman who has just crossed the line from overweight to obese.
When Kay goes on a diet, she adopts an eating pattern that is quite different to her normal one. Typically the diet book urges her to restrict her calories. Most diets want her to reduce her calorie intake by 500 a day, or even 1,000. This means that she has to pay attention to what she eats; alter the way she cooks to reduce portions; give up or strictly limit certain kinds of foods; and she has to count calories, either directly or indirectly. While dieting, she is hungry most of the time and she frequently thinks about food.
The result of this change is that Kay loses, on average, one to two pounds a week. On a conventional diet fat makes up about 75% of this loss. The remaining 25% is muscle. PMC 3648712.
After Kay has achieved the desired weight she resumes her usual eating pattern. But it was this eating pattern that caused her to be overweight in the first place. Returning to it means that she will gradually return to her former weight unless she continues to restrict calories. Most people don’t like being hungry all the time, and so the weight comes back.
So Kay endured hunger for months and the end result is she is just as heavy as before.
But the situation is even worse. This is due to changes the diet causes in her resting metabolic rate (RMR).
RMR is a measure of how much energy is needed to keep the vital functions going. This includes the actions of the heart, brains, lungs and liver, and the energy needed to maintain all other tissue. For an average person, the RMR burns about 70% of the calories consumed.
The human body has marvelous adaptive capabilities. When food is restricted, it senses a starvation situation and it slows down its metabolism to conserve energy. This effect is exacerbated by the loss of muscle mass that the diet causes. Muscle is metabolically active. Also, losing muscle results in a lowering of physical activity.
If the situation occurs again, as in so-called yo-yo dieting, the slow metabolism becomes entrenched.
Once the metabolism is permanently slowed, less calories are needed than before. If Kay returns to her original eating pattern this will cause her to end up heavier than before she started dieting.
If dieting is not the solution, then what is? This book focuses on lifestyle. By adopting a specific lifestyle you can gradually lose weight, with little or no hunger, and keep the weight off for the rest of your life.