Peer-reviewed study

GLP-1s lower fat, but lean mass still needs attention

Comparative Effects of Individual Glucagon-Like Peptide-1 Receptor Agonist-Based Medications on Direct Measurement of Body Composition Among Adults With Overweight or Obesity With or Without Type 2 Diabetes: A Systematic Review and Network Meta-Analysis of Randomised Controlled Trials

PeptidesSystematic review and network meta-analysis of randomized trials2026

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Kris Oddo, NASM-certified personal trainer, is the founder and head coach of Gains From Geebs (Geebs Coaching), a 1:1 online fitness coaching practice.

Quick answer

What this study found

Fat loss can improve while strength, protein intake, and lean-mass monitoring still need attention.

How strong is this kind of study?

Reviews of many studiesThis study
Controlled trials
Observational
Narrative reviews

Systematic review and network meta-analysis of randomized trials. Heavier plates are built from more studies, so they move less when the next one lands.

At a glance

What kind of study this is

Strongest evidence

This pools results from many separate studies, so it carries more weight than any single trial on its own.

Design: Systematic review and network meta-analysis of randomized trials
Published: 2026
Journal: Diabetes, Obesity and Metabolism
Reference: PMID 42209204

Source details

Who ran it, and where to read it.

Authors: Wachiraphansakul et al.

PubMed DOI

Honest limits

What this study does not prove.

This analysis cannot choose a medication or dose for an individual or predict side effects. Those decisions belong in clinician-managed care.

Kris Oddo, NASM-CPT, in the gym — Kris Oddo, NASM-CPT. The study is the evidence; the paragraph below is what he actually does with it.

Kris's practical takeaway

Here's what to do with it.

Fat loss can improve while strength, protein intake, and lean-mass monitoring still need attention.

If you are losing weight

What this means if you're losing weight.

On a GLP-1, about a quarter of the weight that comes off is lean mass. Lifting and enough protein are what you control: they decide how much of the rest is fat. The medication stays with your prescriber.

Keep your muscle on a GLP-1 Lose fat without losing muscle

Ways to use it

Safe ways to apply it.

Body composition beats scale-only thinking

Fat loss still needs a strength signal

GLP-1 weight loss still needs strength and nutrition support

Questions this research helps answer.

GLP-1 nutrition answer

Do GLP-1s cause nutrient deficiencies?

GLP-1s do not automatically cause a deficiency in everyone, but low appetite and reduced intake can create nutrition gaps. Protect protein, fluids, fiber, and nutrient-dense meals while qualified clinicians handle labs and medication care.

Strength tracking answer

Should you track strength while losing weight?

Yes. Strength tracking gives you a practical signal the scale cannot. If weight is dropping but strength, energy, and protein consistency are collapsing, the plan may be costing too much muscle and function.

Related guides and studies

Peptides studies Glp 1 Muscle Preservation Studies Do Glp 1s Cause Muscle Loss Should You Track Strength While Losing Weight

FAQ