Jean-Claude Vacassin on under-fuelled members, moralising fitness culture and why GLP-1s are both a threat and a massive opportunity for coach-led gyms.
GLP-1 use in gyms is no longer theoretical. It’s not a future trend. It’s happening. Some members are open about it and the taboo is fading but plenty aren’t.
They’re turning up under-fuelled, dehydrated, in aggressive calorie deficits and their coaches often don’t know why. That’s where the real challenge starts.
What we’re actually seeing on the gym floor
There are two very different scenarios. The first is easier: long-term clients who change. You know their patterns, their energy and how they normally show up. So when someone who’s usually switched on suddenly looks flat, is losing weight quickly and their energy tanks, you can spot it.
It might not be GLP-1 related. But you can ask the question. Or at least modify sessions accordingly.
The second scenario is harder because it relates to new members. You don’t know their baseline. You don’t know what “normal” looks like for them. They arrive already on GLP-1s, already in a deficit and already not wanting to eat.
GLP-1s suppress appetite, yes. But they also impact reward pathways.
You don’t just lose hunger. You often lose some drive. You lose some training energy. So you’ve got someone in a high calorie deficit with low energy trying to train like they’re fuelled and recovered.
That’s a problem.
It’s much easier when people are upfront. We can modify training, manage volume and intensity and think long term. What’s harder is when people don’t say anything and just grind through sessions half empty. And I suspect as usage becomes more widespread, particularly with oral forms, this issue will only increase.
Most PTs are not prepared for this
If I’m being blunt, I don’t think the average PT is prepared at all.
A lot of trainers still just apply the workout they’ve written to whoever is in front of them.
They’re fine adjusting eight reps to ten. They’re less good at stepping back and asking: should this person even be training like this right now? That requires emotional intelligence, reading the client and being comfortable asking awkward questions.
I also don’t think most trainers realise how prevalent GLP-1 use already is. They know it exists. They know it’s “a thing” but I don’t think they grasp how many of their members are on it. I also think many PTs are nervous about stepping into that territory.
What is the trainer actually responsible for?
Let’s be clear: trainers are not responsible for diagnosing GLP-1 use and you can’t assume every tired client is on Ozempic. But if you’ve got a long-term member and there are radical behavioural or physiological changes, there is an onus to ask questions.
The trainer’s responsibility is awareness and conversation. It’s not prescription advice. It’s not telling someone whether they should or shouldn’t be taking GLP-1s.
That is out of their lane.
GLP-1s, when prescribed properly, are a medical intervention. Trainers should remain agnostic about the decision to use them. But you absolutely have to meet the client where they are. If someone is on them, your job is to adjust the training appropriately. That’s it.
Why people don’t tell you
There’s still a taboo around GLP-1 use. It’s a bit like “gear” for blokes. Some will tell you. Some won’t.
There’s a psychological layer to it. Deep down, many people believe fitness should be earned.
There’s routine, sacrifice, discipline, leaning into effort. That’s the part that changes you. GLP-1s can feel like a shortcut. I’m not calling it cheating. But it feels like one to some people.
And then there’s judgement. “You couldn’t stop using your mouth as a vacuum, so you needed a drug”. People feel sheepish and that makes honesty harder. Ironically, if people were just upfront, both sides would benefit; but the industry doesn’t always make that easy.
The moralising problem in fitness
There is absolutely a moralising tone in parts of fitness. “I built this body through discipline and sacrifice, therefore let me tell you how to live”. There’s this subtle message that a fit body equals a fit mind. It’s a bit eye-roll.
So if you’re using GLP-1s, you feel like you’re stepping into a room where you’re already being judged. That’s not helpful. It’s also naïve. Because GLP-1s will piss some people off. They allow people who haven’t followed the traditional path of sacrifice to arrive in similar physical shape.
That challenges the hierarchy, which is precisely why people keep quiet.
My own view: they have a place, but they’re not magic
GLP-1s have a place. As a medical intervention, for the people they were designed for, they make sense. Where it gets murky is when dosage starts increasing based on seasons, holidays and weddings. That’s a different conversation.
The thing GLP-1s shortcut is the process. Getting into shape changes how you look. But more importantly, it changes how you feel because you’ve earned it. It’s the routine. The sacrifice. The discipline. Leaning into effort.
Shortcutting all of that robs people of something and the data around higher-dose, long-term use is not exactly glowing, even when offset with resistance training.
So you’re choosing your problems. You can be overweight and have problems. Or you can take GLP-1s and have problems. Either way, you’re going to have some problems.
In an ideal world, we’d all eat less and move more. If that worked consistently, we wouldn’t be having this conversation.
So yes, they have a place, but I do think it’s a shame when someone misses out on the psychological benefits of health and fitness because they’ve only taken a pill.
Threat or opportunity for gyms?
GLP-1s are a threat to disengaged gyms.
If your product is “come in, suffer on a cross trainer at the back for 30 minutes because you think you should”, GLP-1s will replace you. But if you run coach-led sessions, focus on strength, build community and support properly? It’s a massive opportunity.
GLP-1s may bring more new gym users through the door than anything we’ve seen before. People lose weight. They feel more confident. They might finally walk into a gym. The question is whether that gym is built to support them properly.
The uncomfortable reality
I joked the other day: why not GLP-1s, testosterone and gear? Suppress appetite, train three times a week and get in amazing shape.
Someone described the result as looking like “a condom filled with walnuts.” It’s a joke but it highlights something real. We are entering an era where intervention is easier than ever.
The gyms that survive will be the ones that double down on what drugs can’t replace: coaching, experience and human judgement.
GLP-1 use in gyms isn’t going away. The only real question is whether we respond like grown-ups or like ideologues.