help me understand lean mass, I have read the wiki twice
help me understand lean mass, I have read the wiki twice. I would rather ask a basic question now than get this wrong quietly for two months.
Two scans on the same machine 24 months apart. Lean mass held better than I expected and the lifts told the same story for free.
Kept the same programme for a year instead of changing it every six weeks. That was the change that worked.
Compared two scans from different clinics and panicked over a difference that was inside the error margin.
Corrections welcome, especially the pedantic ones. Pedantry is how this board earns its reputation.
best — the order this archive was captured in
Some lean mass loss accompanies weight loss in any deficit. Resistance training and adequate protein intake are the two interventions with the best evidence for limiting the proportion.
Started weighing protein rather than estimating it. The gap between what I thought and what I ate was embarrassing.
Have the lifts held, dropped, or moved around?
DEXA has a real error margin and people quote it to one decimal
Strength retention is an imperfect but free longitudinal proxy: it is affected by neural factors and by being in a deficit, so it tracks tissue change loosely rather than exactly.
grip strength and lift numbers are cheap longitudinal markers
Are you comparing against your own baseline or against a published average?
Removed a prescriptive nutrition target aimed at another member. Describe your own intake instead.
Removed a prescriptive nutrition target aimed at another member.
sarcopenia_watch is right that protein becomes a logistics problem when appetite drops.
Correction: those scans are from different machines, and the difference you are describing is within the measurement error.
Right — strength retention is a free proxy and it tracks better than most people expect.
Small fix — that is fat-free mass, not muscle mass. The scan cannot separate them the way the post assumes.
the same DEXA machine or it is not a comparison
losing weight slower does not automatically preserve more lean mass
Same. Volume over novelty. Changing programme every six weeks cost me a year.
Agreed — protein and resistance training. Everything else in these threads is a rounding error on those two.
the same DEXA machine or it is not a comparison
Agreed — and same machine, same conditions, or the two scans are not comparable.
the appetite effect makes eating enough protein a logistics problem
Disagree — slower loss does not automatically preserve lean mass. Protein and training do the work, not the rate on its own.
Yes. Lean mass change during weight loss is expected; the useful question is the proportion, not whether it happens.
the scale cannot distinguish tissue types and never could
That protein figure is grams per day, not grams per kilogram. Different claim entirely.
On comparing yourself to composition figures from trials.
Published composition data comes from supervised populations with structured protocols, standardised scanning, and analysis populations that have been defined in advance. Your two scans at a local clinic, taken in different states of hydration, are not the same measurement.
Use your own baseline. The question worth asking is whether your own trajectory is going the way you want given what you are actually doing, and the honest answer usually requires measuring protein rather than estimating it and being truthful about training frequency. Neither of those is advice — a programme and a target are things to work out with somebody who knows your history.
I would not change the programme on the strength of one scan. The measurement error is larger than the effect you are reacting to.
How to make a DEXA comparison mean anything.
Same machine, same clinic, same protocol. Same hydration and fasting state, as far as you can manage. At least three to four months apart, because the measurement error is large relative to short-term change. Three scans rather than two, because the first pair cannot distinguish a trend from noise.
Do less than that and you have two numbers with an offset of unknown size, which people then react to by rebuilding a training programme. The free alternative — a few tracked lifts and a monthly waist measurement — is directionally informative, costs nothing, and is far harder to over-interpret.
FFMI is a ratio and it moves when either term moves
Lost slower for six months deliberately and my composition change was not obviously different. Training was what mattered.
Hydration status and fasting state affect the lean mass estimate. Standardising both is the difference between a comparison and a coin toss.
DEXA has a meaningful coefficient of variation, and it differs between machines and protocols. Comparing scans from different clinics adds a systematic offset that is invisible on the report.
- 1Some lean mass loss accompanies weight loss in any deficit. Resistance…7 comments in this branch · started by u/noor_ivaturi
- 2the same DEXA machine or it is not a comparison6 comments in this branch · started by u/first_pen_fear