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ForumsCOA & Analytical TestingAmino acid analysis for peptide identity — looking for input

Amino acid analysis for peptide identity — looking for input

SleepFixSam Wed, Mar 5, 2025 at 2:02 PM 13 replies 1,784 viewsPage 1 of 3
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SleepFixSam
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Hawaii
Mar 5, 2025 at 2:02 PM#1

I tracked honestly for two weeks and averaged 68g of protein against a target of about 120g. That gap is the whole problem and no meal plan I have found is written for it.

The arithmetic that makes it tractable: reference weight in kg times 1.6 gives the target; divide by four for a per-sitting figure; then find four foods that hit that figure in a volume you can actually finish. Most people need two of the four to be liquid or semi-liquid early on.

The bit I cannot resolve on my own is whether the RDA is the wrong reference entirely during rapid weight loss, and what the actual target should be.

I have searched first, so if this is covered somewhere point me at it and I will read it.

30 0pete_nash, hank_denver, carlos_SATX and 27 others
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Dr.SportsMedIN
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Mar 5, 2025 at 3:25 PM#2

Short answer first, then the reasoning. The RDA is the wrong reference and it is worth understanding why. 0.8 g/kg is the intake at which nitrogen balance is not negative in healthy weight-stable adults — a floor for deficiency prevention, not an optimum, and derived in a population that is not in a deficit. In a substantial energy deficit, protein requirement rises because amino acids are being oxidised for energy and because muscle protein synthesis is blunted. The literature on preserving lean mass during weight loss lands around 1.4 to 2.0 g/kg of reference body weight, which is roughly two to two and a half times the RDA.

29 24lisa_labSD, adam_van, Dr.SurgeonPGH and 26 others
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tane_welly
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Wellington, NZ
Mar 5, 2025 at 4:48 PM#3
Dr.SportsMedIN said:
The RDA is the wrong reference and it is worth understanding why.

True, and anyone with reduced kidney function needs that target set by a clinician rather than a forum. High protein is safe in normal kidneys and is not automatically safe in impaired ones.

28 23DanielChem_CHI, marco_milano, pam_columbus and 25 others
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cory_ATX
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Austin, TX
Mar 5, 2025 at 6:11 PM#4
SleepFixSam said:
I tracked honestly for two weeks and averaged 68g of protein against a target of about 120g.

This matches mine closely enough to be worth saying so. Distribution matters less than total but it is not nothing. Roughly 25 to 40g per sitting with enough leucine to trigger synthesis, three or four times a day, is more effective than the same total in one enormous evening meal — and on a suppressed appetite the enormous evening meal is the one you will not finish anyway.

27 22Dr.PathRoch, mona_PHX, andrew_nyc and 24 others
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sophie_paris
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Paris, FR
Mar 6, 2025 at 2:15 AM#5

Adding the clinical framing, because it changes how the question reads.

DEXA scan update relevant to protein intake:

Scanned at months 0, 6, and 12. Here are the body comp numbers:

BaselineMonth 6Month 12
Total mass259 lbs214 lbs196 lbs
Fat mass99 lbs79 lbs46 lbs
Lean mass152 lbs154 lbs153 lbs
Body fat %44%34%25%

Lean mass preserved — actually GAINED 1-2 lbs thanks to progressive overload + 1.5g/kg protein. The protein intake discussion needs to include body comp data, not just scale weight.

Last edited: Mar 6, 2025 at 7:15 AM
26 21BethLabQueen, ChrisMacros, KetoKyle and 23 others
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