Topic summary

Interpreting a composition change that is within the error bars

Outcomes › Body composition bioimpedance data table lean mass loss

This is a generated summary. It shows the 5 most-liked posts from a topic of 23, in their original order, with the accepted answer included where one exists. It is a reading aid and it will miss nuance — the full topic is the record.

m.marchettiTL2 Moderator15 Jun 2025#4

methods_draft, post #3: post #2 is right about the mechanism and I think understates the practical bit. Comparison to published data: the trials reported mean fat and lean mass changes. Individual results vary around that mean. Being above or below average is not a sign of something wrong. Go to post

Worth separating two things that post #3 runs together.

Resting metabolic rate: body composition affects metabolic rate. As fat mass decreases and lean mass is maintained, metabolic rate is usually maintained better than with simple weight loss alone.

16 likes in reply to #3 13mo

p.lindqvistTL2 Moderator26 Jun 2025#8

k.adeyemi, post #6: Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound. Go to post

On post #4 — agreed on the reasoning, with one qualification.

Ultrasound: thickness of subcutaneous fat at specific sites. Less standardised than DXA and operator-dependent. Useful as a supplementary measure but not as a primary method.

22 likes in reply to #6 13mo

CSagredoTL3Regular29 Jun 2025#9

m.marchetti, post #4: Worth separating two things that post #3 runs together. Resting metabolic rate: body composition affects metabolic rate. As fat mass decreases and lean mass is maintained, metabolic rate is usually maintained better than with simple weight loss alone. Go to post

DXA (dual-energy X-ray absorptiometry): the standard for body composition in research. Precision is roughly ±1 kg for lean mass. Two scans six months apart on the same machine with the same technician give you useful information. Two scans six weeks apart on different machines tell you about the machines.

23 likes in reply to #4 13mo

r.chukwuTL2 Moderator3 Jul 2025#11

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

18 likes in reply to #3 13mo

e.halonenTL2 Moderator19 Jul 2025#18

Picking up post #15: that is the part I would want checked first.

Comparison to published data: the trials reported mean fat and lean mass changes. Individual results vary around that mean. Being above or below average is not a sign of something wrong.

26 likes 12mo

Read the full topic (23 posts)

This topic was referenced in

DXA precision and the least significant change for lean massOutcomes › Body composition · 85 replies
Circumference measurements as a poor man's composition estimateOutcomes › Body composition · 112 replies
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