Two scans six weeks apart on different machines: a cautionary tale

On the subject in the title: Two scans six weeks apart on different machines: a cautionary tale Working notes rather than a conclusion.

Longitudinal report with the method stated, because a number without a method is not a measurement.

Same scale, same time of day, same conditions, 34 weeks. I have also recorded protein intake and resistance-training sessions, both self-reported and both therefore optimistic.

The reason I am posting is a pattern in the middle of the series that I cannot explain and that I suspect is measurement rather than signal.

Lean mass loss during rapid weight reduction: depends on protein intake, resistance training volume, and total energy deficit. Adequate protein and maintaining training intensity both help preserve lean mass.

Picking up post #6: that is the part I would want checked first.

Precision versus accuracy: the precision you need depends on what question you are answering. "Am I losing fat?" requires less precision than "Is my lean mass preservation within the expected range?"

On post #22 — agreed on the reasoning, with one qualification.

Maintenance phase: tracking body composition during maintenance (weight stable) is different from tracking during active loss. Changes are smaller and precision becomes more important.