PeptideStack
5.2kquestions
20kanswers
220users

What fraction of loss on dulaglutide is lean mass according to SURMOUNT-2?

Asked 5 Jul 2025Modified 11 months agoViewed 32k times
24

Setup, so nobody has to ask: dulaglutide · SURMOUNT-2.

I would like help reading this properly rather than being told what conclusion to reach.

I have the full report including the method section, so I can quote specifics if that helps.

What would I need in addition before this supported a decision?

lean-mass
lean-mass

Lean body mass as measured rather than assumed: what DEXA, BIA and air-displacement plethysmography each actually estimate, the body-composition…

164 questions
muscle-loss
muscle-loss

Loss of contractile tissue during energy deficit: what fraction of total loss is lean mass, why the commonly quoted figures are measurement…

82 questions
dexa
dexa

Dual-energy X-ray absorptiometry: what it measures, its precision limits, why hydration state and scan positioning move the numbers, and how to…

84 questions
shareeditfollowflag
CD
askedcolm_dunphy16k165 Jul 2025

5 Answers

Accepted answer first, then by votes
23

Accepted answer

The part that matters: what the data supports is narrower than what gets recommended, so it is worth separating the two.

Absolute strength holds up better than scale weight during a deficit for a straightforward reason: strength is substantially neural and skill-based, and the contractile tissue you retain is being trained harder relative to its size. Grip strength and repetition maxima are therefore lagging indicators of muscle loss rather than leading ones, which is an argument for measuring both.

Protein target, worked: at 88 kg, a target of 1.6 g/kg is 88 × 1.6 = 141 g per day. Spread across three eating occasions that is roughly 47 g each, and the leucine threshold for a maximal muscle protein synthetic response is met at around 2.5 to 3 g of leucine, which corresponds to roughly 30 to 40 g of a high-quality protein. So three meals at 40 g plus one 25 g snack gets you to 145 g and clears the per-meal threshold each time. On 900 kcal that leaves about 340 kcal for everything else, which is the actual constraint.

SURMOUNT-4 provides the cleanest maintenance-versus-withdrawal contrast available in the class, and it is the reference for any claim about what happens after stopping[1].

The plateau is arithmetic. Treat it as arithmetic and the response follows.

shareimprove this answerflag
DB
answered · acceptedDr_Fatima_Belkacem52k1388 Aug 2025
8Two of us worked through this independently and arrived here, so it is at least reproducible. – a_lindgren 44 days ago
7Worth adding that the method section is where the answer usually is. – RP_C18 10 months ago
add a comment
Sponsored

PeptideMeter - Independent Peptide Analytics

Aggregated, published test results and vendor ratings built from submitted batches. Methodology stated, dataset browsable, no listing fees.

Browse results
22

The distinction that resolves this is between proportional loss and functional loss. Losing lean mass in proportion to total mass is what happens in every weight loss intervention. Losing function is not, and function is measurable.

The minimum effective resistance-training dose in a deficit is lower than most programmes assume. Two sessions a week covering the major movement patterns, with loads taken close to failure, is sufficient to retain most of what would otherwise be lost. Volume beyond that adds recovery cost that a large energy deficit is poorly placed to pay.

The regain trajectory after stopping is roughly a mirror of the loss trajectory, and it is not primarily a willpower phenomenon. Appetite signalling returns, energy expenditure remains suppressed relative to the original mass, and the two combine. That is an argument for a maintenance plan existing before the stop, rather than an argument against stopping.

The STEP 1 extension reported substantial regain in the year after treatment withdrawal, with weight and cardiometabolic variables trending back toward baseline[1].

The limitation of the arithmetic is that it assumes intake is being measured accurately, and self-reported intake is systematically underestimated by a substantial margin.

Two resistance sessions a week and a protein target you actually hit will do more than any refinement beyond them.

shareimprove this answerflag
UM
answeredunit_math13k1816 Jul 2025
14

Start with the arithmetic, because the answer to the practical question is usually a number and the number is usually achievable.

DEXA precision is better than people assume for fat mass and worse than people assume for lean mass in a single scan — the least significant change for regional lean mass on a well-maintained scanner is on the order of a few per cent. That means two scans three months apart can differ without anything having happened, and it means a scan sequence needs to be at least three points before a trend is interpretable.

Food noise returning is not obviously tolerance. Receptor desensitisation is one hypothesis; a second is that the initial effect was partly novelty and partly the steep early deficit, and a third is that intake has drifted upward and the signal is being outcompeted rather than weakened. The three make different predictions about what a dose increase would do.

I would be careful with the supplement literature here; effect sizes are small, the studies are mostly in trained young men, and generalisation to a large deficit is not obviously valid.

A maintenance plan written before you need it is worth more than a better loss plan.

edited 14 Aug 2025 by micron22 — tightened the wording; no substantive change

shareimprove this answerflag
MI
answeredmicron2236k13828 Jul 2025
3Worth adding that the method section is where the answer usually is. – Dr_Bram_Verhoeven 4 months ago
add a comment
9

The commonly quoted figures for lean-mass loss are mostly measurement artefacts, and the artefact is well understood: fat-free mass as measured includes water and glycogen, both of which fall early and neither of which is contractile tissue.

Hydration state moves a DEXA lean-mass figure directly, because the algorithm assigns water to the lean compartment. Scanning fasted, at the same time of day, before training and without a recent high-carbohydrate day is the difference between a comparable sequence and a noisy one. Bioelectrical impedance is far more sensitive to hydration again, which is why its trend is unusable at this timescale.

The evidence for a higher protein intake preserving lean mass during an energy deficit is reasonably strong in resistance-trained populations and weaker in sedentary ones, with the meta-analytic estimates supporting intakes in the region of 1.6 g/kg over lower intakes when training is present[1].

The caveat is that population averages tell you about populations. Your own trajectory is a sample of one and should be read as a trend, not as a deviation from a published mean.

Train, eat the protein, measure something functional, and give the trend three months before you interpret it.

shareimprove this answerflag
TM
answeredtobias_maartens94k25819 Aug 2025
The placebo-arm figure is the part everyone omits. – h_pergande 7 months ago
add a comment
6

On the detail: the mechanism is worth having straight, because it predicts which interventions can work and which cannot.

Fibre at very low total intake is a trap. Soluble fibre needs water and motility to work; insoluble fibre adds bulk to a slow transit. At 900 kcal a day with delayed gastric emptying, an osmotic agent is more predictable than a bulking one, and adequate fluid is doing more work than either.

The body-composition substudies in the major programmes consistently report that the proportion of weight lost as fat mass is approximately three quarters or better, with the lean-mass fraction falling within the range seen in dietary weight loss of comparable magnitude[1].

Worth stating that a DEXA sequence is only as good as its protocol consistency, and most people’s sequences are not consistent enough to support the conclusions drawn from them.

Measure strength as well as mass. It is cheaper, it is less noisy, and it is closer to what you actually care about.

shareimprove this answerflag
DF
answeredDr_Colm_Fitzhenry85k24830 Aug 2025

Your answer

Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.

Not medical advice. Research-use-only compounds are not approved for human use.