Dieting is futile. Very few people manage a large percentage weight loss for more than a year. Frustration and weight cycling - losing and gaining back weight repeatedly - are the most common result. That's bad enough, but does dieting cause more serious problems?
It has long been thought that weight loss and weight cycling causes changes in your body that actually make you wind up fatter in the long run, and pushing your weight down may cause emotional disorders like depression and bulimia. A consortium of smart doctors sponsored by The National Institutes of Health, called the "National Task Force on the Prevention and Treatment of Obesity" has recently published and examination of the issue of dieting and emotional disorder.
The idea that dieting and weight loss would cause psychological consequences dates from way back during World War II when Ancel Keys & al. did a famous experiment on starvation. He starved some young men who were conscientious objectors to the war and who had volunteered for this experiment. They lost 25% of their weight and got very miserable and hungry but remained otherwise physically healthy. The most remarkable finding of the starvation experiment was the psychological effect. These guys thought about food constantly and lost interest in everything else, including sex. They found out that hunger hurts a lot. After they were allowed to eat again, they would often binge and keep eating when their stomachs were too full to keep anything else down.
The National Task Force on the Prevention and Treatment of Obesity found no big problems however, in their review of studies since the starvation experiment. They found that there was not a significant increase in bulimia if dieters did not lose more than 10% of their baseline weight.
It is important to recognize that you should look at percentage weight loss rather than number of pounds when judging weight loss and its consequences. Twenty-five pounds caused the starvation syndrome in Dr. Keys' subjects but 25 lbs would not hurt someone who weighs more than 250 lbs.
There is a good new idea out and about in the land of dieting and that is - you should aim for 10% weight loss but no more - no matter that you may not be totally thin. Ten percent is easy to calculate and achieve and most importantly it's possible to maintain. Just 10% weight loss gives a lot of benefit to cholesterol and sugar and blood pressure without the pain of starvation and the heartbreak of weight yo-yoing.