Final answer:
Type 2 diabetes can be reversed or its progression stopped by lifestyle changes, especially increased physical activity. The power of fitness also aids in the recovery from disorders such as anorexia nervosa by improving various health parameters.
Step-by-step explanation:
The health condition that was reversed in the power of fitness, as described by the provided details, is type 2 diabetes. It's been shown that lifestyle changes, including increased physical activity, can have a profound impact on this condition.
The positive effects of fitness and exercise extend beyond weight management; they include enhancing cardiovascular and muscular fitness, bone density, cognitive function, and can also contribute to the management of diseases such as heart diseases and diabetes.
An example provided is the case of anorexia nervosa, an eating disorder, which can lead to severe emaciation and health deterioration.
With proper treatment, which can involve a comprehensive approach including nutritional support and psychological therapy, and the incorporation of fitness, notable health improvement and even reversal of this condition can be achieved.