Zone 2, Keto, Rapamycin & GLP-1s: Are We Gatekeeping Longevity?

Longevity is having a cultural moment. From zone 2 cardio workouts filling Instagram feeds, to ketogenic diets touted as brain-boosting, to whispers of rapamycin as an anti-ageing pill and the meteoric rise of GLP-1s like Ozempic, it feels like everyone is chasing the holy grail of living longer.

But how much of this is genuine science and how much is just clever marketing? More importantly, are we unintentionally gatekeeping longevity by spotlighting expensive drugs and niche interventions while overlooking the basics?

To cut through the noise, we asked Dr. Darshan Shah, a physician at the forefront of integrative and preventative medicine, to weigh in on the state of these longevity tools. FYI - his answers may surprise you. While he acknowledges the potential of these buzzy interventions, he’s pretty clear that context, timing and lifestyle foundations matter far more than hype. Buckle up.

Are these tools science or just hype?

When asked if zone 2 cardio, ketogenic diets, rapamycin, and GLP-1s are legitimate longevity tools or just science-flavored hype, Dr. Shah doesn’t hesitate. “I do think all of these are genuine tools that everyone should be looking at to accelerate their longevity journey. However, it’s very personal and you have to find what works for you. Certain things will work for certain people much better than others. You really have to experiment with what fits into your lifestyle and where you are on the longevity journey,” he says. In other words, the interventions themselves aren’t fraudulent but they’re not universally applicable either. The real key is personalisation.

So, are we gatekeeping longevity?

Many of the longevity conversations online fixate on futuristic drugs or elite biohacking gadgets, but Dr. Shah believes this creates a distorted picture. “We are putting all of these expensive, inaccessible interventions under the term longevity, which is something I’m really concerned about. True longevity is about doing the basics first by getting your lifestyle in order, followed by functional medicine to dig deeper into areas that are traditionally ignored by Western medicine and then using preventative and diagnostic tools much earlier than we currently do,” he clearly explains. He likens it to a pyramid. “These advanced interventions are really the tip of the pyramid. As doctors, we need to meet people where they are and guide them through lifestyle foundations before jumping into tools like rapamycin or GLP-1s too early.”

For Dr. Shah, longevity starts with sleep, movement, nutrition, stress management and early detection… not injectables or prescription drugs.

Zone 2 cardio: secret hack or just steady-state exercise?

Zone 2 training is when you maintain a heart rate where you can still hold a conversation and has been labeled a “longevity hack” by fitness influencers. But is it really that groundbreaking? “There’s a lot of attention on zone 2 because people are just not moving enough. If you incorporate it as just another way of walking with intention, then you are really benefiting. If you’re at the beginning of your journey, just go for a walk. Don’t worry about lactate thresholds or fancy trackers,” says Dr. Shah.

For most people, simple daily walking is the gateway to better metabolic health. “Aiming for around 8,000 steps a day is where the research takes me,” he says. High-tech lactate meters and VO2 max testing may be useful for advanced biohackers, but for the average person, the message is simple: walk more and walk consistently.

Ketogenic diets: longevity strategy or short-term fix?

Keto has been promoted as everything from a fat-burning miracle to a brain-health saviour, but does it actually extend your lifespan? “In my opinion, ketogenic diets are a temporary intervention that people can use for weight loss or as an elimination diet. They’re not really sustainable long term and many people do experience elevations in cholesterol,” Dr. Shah adds.

That doesn’t mean keto is useless. In fact, Dr Shah points to some compelling therapeutic uses. “Keto can be extremely helpful in people with brain health issues such as cognitive impairment, depression and even schizophrenia. There’s great work by Chris Palmer and Dale Bredesen showing improvements in these conditions.”

Still, he cautions against it blindly and long-term. “You always want to do a ketogenic diet with biomarker testing and guidance from a practitioner - particularly tracking cholesterol, inflammation and metabolic health markers. Elevations of cholesterol (especially ApoB levels) can be dangerous - particularly if inflammation is also present. The bottom line: keto can be a powerful short-term tool, but not necessarily a sustainable lifestyle for everyone.

Rapamycin: breakthrough or overhyped?

Rapamycin is one of the most hyped drugs in the longevity world. Originally developed as an immunosuppressant, it has shown promise in extending lifespan in mice. But what about humans? “There is no strong evidence at all in humans, although studies are underway. There’s a lot of promise in mouse models, particularly through the ITP (Interventions Testing Program). But this should definitely not be the first thing you do.”

Dr. Shah is clear that rapamycin is for the extreme longevity enthusiast, not someone just starting their journey. “It’s experimental, with potential side effects like mouth ulcers or apathy. There are many other interventions that are less expensive, less experimental and with fewer risks that people should focus on first,” he adds. Essentially, rapamycin may one day prove groundbreaking, but right now, it’s still in the realm of biohacker experimentation and not mainstream medicine.

GLP-1s: longevity or just quick weight loss?

GLP-1 drugs like Ozempic and Wegovy are dominating headlines and social feeds for their dramatic weight loss effects. But are they purely cosmetic or do they influence aging itself? “Weight loss is 90% of the benefit,” Dr. Shah says. “By improving metabolic health, reducing visceral fat and lowering inflammation, they clearly support healthspan.”

He also sees broader possibilities: “There’s evidence GLP-1s affect the immune system and brain health directly, so they may have longevity benefits beyond weight loss.” One common fear is that GLP-1s cause muscle loss but Dr. Shah pushes back. “I think the muscle loss problem is overblown. In our clinics, we pair GLP-1s with proper muscle-building protocols, and we’ve actually seen people gain muscle. If you use them irresponsibly (sitting around and eating ultra-processed foods) you’ll lose muscle. Used correctly, they can help reset your relationship with food and exercise,” he adds. The verdict? GLP-1s may not be a silver bullet, but when used responsibly, they can be a legitimate tool for improving metabolic health and healthspan.

Which interventions will stand the test of time?

When asked which of these tools will become staples of longevity, Dr. Shah is pragmatic. “I would say zone 2 cardio, dietary modifications and GLP-1s (particularly when supported by gut health and fiber) are already time-tested and we’re just diving deeper into the science. Rapamycin still has a giant question mark in my head,” he says. In other words, the basics like movement, diet and metabolic health remain the best tools and. experimental drugs may (or may not) join them in the future.

Science vs. behavior: the true longevity barrier

So what’s the biggest roadblock to longer lives: scientific innovation or human behavior? “The reality of human behavior, specifically lifestyle interventions, is the biggest barrier to reversing chronic disease and improving healthspan,” says Dr. Shah. “Right now, the greatest benefit we can achieve is adding quality life to the last 20-30 years of our lifespan.”

He believes radical lifespan extension (adding 50+ years beyond today’s maximum) will require breakthroughs at a cellular level. “Truly extending lifespan will only come from things like Yamanaka factors or advanced pharmacology. We don’t yet have anything that can push humans beyond our current maximum lifespan of about 120 years,” he adds. Until then, the focus should be on our healthspan… living better, not just longer.

Final thoughts

There’s no denying that the longevity conversation is louder than ever, but as Dr. Shah reminds us, most of these tools are only a small part of the picture. Zone 2 cardio, dietary changes, rapamycin and GLP-1s each have a place, but without foundational lifestyle changes, they risk being little more than expensive distractions. Longevity isn’t about finding a single magic pill. It’s about building a solid pyramid with lifestyle first and advanced tools later. That, and remembering that the greatest gains may come not from science fiction breakthroughs, but from walking more, eating better and preventing disease earlier.

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