Table 1.
Loss of muscle mass and adjustments in muscle morphology and muscle physiological function in underweight individuals with anorexia nervosa were found to be similar to the adaptations in muscle in response to experimental long-term starvation in healthy young adult men.
| Experimental Starvation | Anorexia Nervosa | |
|---|---|---|
| Body weight loss | 12–25% | 20–40% |
| Muscle mass loss | 20–41% | 20–30% |
| Muscle morphology | fiber atrophy, ↓↓ type II | fiber atrophy, ↓↓ type II |
| Muscle physiology | ↑ contractility 10 Hz | ↑ contractility 10 Hz |
| Muscle innervation | intact | intact, unless BMI~12.5 |
| Work capacity | ↓ 20–40% | ↓ 30–49% |
| VO2 max | ↓ | ↓ |
| Endurance | ↓ | ↓ |
| Increased urge to move | absent | present |
| Motor restlessness | rare, short-lived | continuous |
| Daily activity level | reduced | maintained, unless BMI~12.5 |
| Psychological changes | present | present |
| Psychopathology | absent | present, multiform |