Step 13: Understand How
“Weightlessness” Comes Into Play In Eating Disorders, and Work To Counteract Its Effects
Why This Is So Important
Skeletal muscle is intensely responsive to use and disuse1. After only a few months of disuse, skeletal muscles will atrophy (or shrink) to less than half of their original size2. This is why surgical patients are gotten out of bed so rapidly now, usually within a day or two of their surgeries, and why paraplegics and quadriplegics are given intense physical therapy to maintain muscle mass. In anorexia, the more weight is lost, the less demand is placed on the bones and muscles, leading to further atrophy. On yet another level, the body moves away from homeostasis.
Within the three or four months of the onset of anorexia our child had lost over 25% of her body weight in spite of the fact that she had realized after the first month that dieting was a serious mistake. She was now eating generous portions at buffets and restaurants, and reasonably well at home, but still continued to lose weight and muscle. The weight loss seemed unstoppable—like a quick elevator ride down—until her weight reached about 61 pounds. This seems to be typical of many cases of anorexia, with a rapid weight loss of about 25% of the total body weight, followed by a “bottoming out” and slowly beginning to regain some of the lost weight.
Although we were encouraged by the fact that our child was eating well, we could not understand why the weight loss did not stop and reverse itself sooner. (I now believe that the loss of body insulation and subsequent heat loss, coupled with the shrinkage of the intestinal tract and loss of digestive capacity, explain why it is so difficult to replace lost body mass, as discussed elsewhere in this book.)