Numbers first: mazdutide · SELECT.
This is presented as though it settles something, and I am not convinced it does.
I have two documents that appear to disagree, which is what prompted this.
What does this actually establish, and what does it not?
Worth being precise here: a plateau at four to six months is the expected shape of the curve, not a failure of it. Energy expenditure falls with mass, and the deficit closes itself unless intake falls further.
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.
| Method | Measures | Sensitive to | Least significant change |
|---|---|---|---|
| DEXA | Three-compartment by attenuation | Hydration, positioning | ~2–3 % regional lean |
| BIA (consumer) | Impedance, modelled | Hydration, food, temperature | Not usable at this timescale |
| Air displacement | Two-compartment by density | Lung volume, hair, clothing | ~1–2 % fat mass |
| Tape and scale | Circumference, mass | Technique | Surprisingly usable as a trend |
On the detail: 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 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].
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.
Train, eat the protein, measure something functional, and give the trend three months before you interpret it.
edited 23 Oct 2024 by Dr_Nadia_Farsi — updated for the 2026 guidance change
Analytical standards and reagents with traceable certificates. Every quantitative result you read inherits the accuracy of the standard behind it.
Shop standardsIn practice, start with the arithmetic, because the answer to the practical question is usually a number and the number is usually achievable.
The first four weeks of loss is substantially fluid and glycogen. Each gram of stored glycogen carries roughly three grams of water, and total glycogen is on the order of 400 to 500 g, so the obligatory water shift alone accounts for a couple of kilograms. This is why the first month looks dramatic and the second looks like a plateau when in fact the fat-loss rate has not changed.
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.
Adaptive thermogenesis — a fall in energy expenditure beyond that predicted by the change in body composition — is documented across weight-loss interventions and is the mechanistic basis for the plateau being expected rather than anomalous.
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.
The plateau is arithmetic. Treat it as arithmetic and the response follows.
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.