Programming Considerations for Clients on the Weight Loss Jabs

Exercise and Weight-Loss Jabs: What This Means for Personal Trainers
GLP-1 and dual-agonist “weight-loss jabs” (e.g., semaglutide, tirzepatide) are changing the fat-loss landscape. Clients arrive lighter, hungrier less often, and sometimes weaker. For personal trainers, the opportunity is clear: pair effective medication with intelligent training and nutrition so weight lost is mostly fat, fitness improves, and strength is protected (Wilding et al., 2021; Jastreboff et al., 2022).
New England Journal of Medicine

These medicines reduce appetite, slow gastric emptying, and improve glycaemia, driving large weight loss (often 15–25%) (Jastreboff et al., 2022). That loss includes fat mass—and some lean mass—so coaching must prioritise muscle retention (Look et al., 2025; Rochira et al., 2024). New England Journal of Medicine PMC

Across STEP (semaglutide) and SURMOUNT (tirzepatide), DXA data show substantial fat loss with smaller, but real, lean-mass loss (Wilding et al., 2021; Look et al., 2025). That’s not unique to jabs—dieting alone also reduces lean mass and absolute VO₂max—but structured exercise limits the damage (Weiss et al., 2017). Your plan should assume lean-mass risk and train against it. New England Journal of Medicine PMC

Randomised data show combining GLP-1 therapy with supervised exercise beats either alone for weight loss quality and health markers—reducing abdominal obesity and inflammation and supporting bone health (Sandsdal et al., 2023; Jensen et al., 2024). Practically: 2–3 weekly full-body resistance sessions plus 150–300 min/wk mixed-modal aerobic work, scaled to training age and side-effect profile. PMC

Resistance training first. Aim to keep or build strength with 6–12 hard sets per muscle per week, using compound lifts and progressive overload. Evidence shows resistance training during energy deficit helps preserve lean mass (Lopez et al., 2022).PMC

Aerobic conditioning. Maintain or raise VO₂max with intervals and tempo work; dieting without training can drop cardiorespiratory fitness (Weiss et al., 2017). 

Protein targets. Push total daily protein towards ~1.6 g/kg/day (younger adults often need ≥1.6 g/kg to maximise lean-mass retention with lifting) (Nunes et al., 2022; Bagheri et al., 2023; Zhao et al., 2024). Spread across 3–5 meals with 0.3–0.5 g/kg per feeding. 

Bone and connective tissue. Include loaded carries, jumps/landings (as tolerated), and heavy lower-body work; combination therapy with exercise appears to better preserve bone outcomes than medication alone (Jensen et al., 2024).

Side-effect-aware coaching. Early nausea and fatigue are common. Use shorter sessions, RPE-based progression, and steady hydration.

Maintenance planning. When doses reduce or stop, weight-regain risk rises. Habit-based exercise alongside continued activity support improves maintenance after pharmacotherapy (Jensen et al., 2024; Horn et al., 2025).

New England Journal of Medicine
Horn, D.B. et al. (2025) ‘Tirzepatide for maintenance of weight reduction’, Obesity Reviews. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC12477106

Sidenote: there’s emerging work on semaglutide and lean mass/function you may want to watch (Ditzenberger et al., 2024). Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11848261

The jab helps you eat less; training tells your body what to keep.
We’ll protect muscle, strength, and fitness. Expect structured resistance training, purposeful cardio, and a protein plan.
This is long-term. Obesity is chronic; training and nutrition skills are your “forever tools,” with or without medication.

Weight-loss jabs are powerful. Trainers who integrate resistance training, aerobic conditioning, protein-forward nutrition, and bone-protective loading will turn “less weight” into “more health and performance.” That’s the competitive edge—and the ethical one.

Bagheri, R. et al. (2023) ‘Effects of 8 weeks of resistance training with different protein intakes’, Biology of Sport. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC10342203/
Jastreboff, A.M. et al. (2022) ‘Tirzepatide once weekly for the treatment of obesity’, NEJM. Available at: https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
New England Journal of Medicine
Jensen, S.B.K. et al. (2024) ‘Healthy weight loss maintenance with exercise, GLP-1 RA, or both’, eClinicalMedicine. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC10965408/
Jensen, S.B.K. et al. (2024) ‘Bone health after exercise alone, GLP-1RA, or both’, JAMA Network Open. Available at: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2820308
Lopez, P. et al. (2022) ‘Resistance training and body composition’, Sports Medicine. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9285060/
Look, M. et al. (2025) ‘Body composition changes with tirzepatide (SURMOUNT-1)’, Diabetes, Obesity and Metabolism. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11965027/
Nunes, E.A. et al. (2022) ‘Protein intake to support resistance training-induced gains’, Journal of Cachexia, Sarcopenia and Muscle. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC8978023/
Rochira, V. et al. (2024) ‘Tirzepatide and body composition’, Nutrients. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11431103/
Sandsdal, R.M. et al. (2023) ‘Combination of exercise and GLP-1 RA’, Cardiovascular Diabetology. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9960425/
Weiss, E.P. et al. (2017) ‘Effects of weight loss on lean mass, strength, and VO₂max’, Medicine & Science in Sports & Exercise. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC5161655/
Wilding, J.P.H. et al. (2021) ‘Once-weekly semaglutide in adults with overweight or obesity (STEP 1)’, NEJM.  https://www.nejm.org/doi/full/10.1056/NEJMoa2032183