I love the phrase metabolic derangements. It accurately conveys how completely abnormal the changes are.
It seems melodramatic to me. And these abnormal changes can be mitigated by walking those 10,000 steps a day they reduced their activity by. That requires a conscious effort, but it's not an onerous burden.
You are perhaps thinking about the psychiatric usage implying a significant mental disorder, but here it just means that the system (i.e. metabolism) has been disturbed in its function, e.g. that it is out of normal range.