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

Amino acid analysis for peptide identity — looking for input

MeganSA_TX Sun, Oct 12, 2025 at 6:34 PM 16 replies 1,337 viewsPage 1 of 4
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MeganSA_TX
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Oct 12, 2025 at 6:34 PM#1

My appetite is suppressed enough that hitting a protein target is now the hardest part of the day, and everything I read assumes I can simply eat more.

What I actually want to know is whether the RDA is the wrong reference entirely during rapid weight loss, and what the actual target should be.

Numbers rather than impressions, if you have them.

42 12PharmD_Rodriguez, julia.endo, JessicaM_2024 and 39 others
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PharmacoVig_BOS
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Oct 12, 2025 at 8:57 PM#2

This one has a reasonably settled answer, so here it is. On a suppressed appetite the winning strategy is protein density per unit of volume, not per calorie. Isolate powders, Greek yoghurt and cottage cheese, egg whites, lean fish, and tinned tuna all deliver a lot of protein in a small physical volume. Front-load it: appetite is usually least suppressed in the first hours after waking and worst on the day or two after dosing, so get the majority in early in the day and early in the week.

Last edited: Oct 12, 2025 at 11:57 PM
41 11Dr.GutHealth, amsterdam_pete, LondonLisa and 38 others
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pat_auckland
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Oct 12, 2025 at 11:20 PM#3
PharmacoVig_BOS said:
On a suppressed appetite the winning strategy is protein density per unit of volume, not per calorie.

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.

40 10LarryQC_SD, wanda_boise, NurseAsh_DET and 37 others
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kim_atl_prep
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Oct 13, 2025 at 1:43 AM#4
MeganSA_TX said:
My appetite is suppressed enough that hitting a protein target is now the hardest part of the day, and everything I read assumes I can simply eat…

This matches mine closely enough to be worth saying so. 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.

I would rather be corrected than agreed with, if it comes to it.

Last edited: Oct 13, 2025 at 7:43 AM
39 9SleepDoc_PDX, RegAffairsDC, BiostatsBrad and 36 others
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anders_CPH
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Oct 13, 2025 at 3:59 PM#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 mass284 lbs244 lbs221 lbs
Fat mass124 lbs84 lbs56 lbs
Lean mass162 lbs155 lbs158 lbs
Body fat %45%35%25%

Lean mass preserved — actually GAINED 1-2 lbs thanks to progressive overload + 1.6g/kg protein. The protein intake discussion needs to include body comp data, not just scale weight.

38 8ChrisMacros, KetoKyle, CanadaChris and 35 others
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