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Summit of Greatness 2024 | September 13-14 | Los Angeles, CA


Dr. David Sinclair

How to Stop Aging (Can Humans Become Immortal?)

What if we didn’t have to grow old?

What if we didn’t have to grow old?

According to research conducted by my guest today, we might not have to.

Dr. David Sinclair is an expert in the aging process. His ground-breaking research is controversial, but recently he’s begun to prove that humans might be able to slow and even reverse parts of the aging process. It’s fascinating stuff!

I had Dr. Sinclair on The School of Greatness about nine months ago, and we had a great conversation! But I knew there was more to explore, so I knew I had to bring him back to continue our conversation.

Today, we’re diving deep. We’re going to discuss the possibility of immortality — whether humans will ever be able to live forever. We’re also discussing ways we can all make the most out of every moment and maximize our bodies’ potential.

Here’s the thing: Getting older doesn’t have to mean getting old. We can stay young at heart forever, and Dr. Sinclair is going to teach us all how to do it. If you’re ready to learn how to pump the brakes on the aging process and stay younger, healthier, and happier for longer, read on!

Who Is David Sinclair?

Even as a child, Dr. David Sinclair was struck by the unfairness of the aging process.

When he was only four years old, his grandmother cautioned him to make the most of every moment with his beloved pet cat, since animals experience shorter lifespans than we do. This instilled a drive in David to fight the forces of time, one that carried him through his adult education.

Dr. Sinclair attended Sydney’s University of New South Wales, receiving both a Ph. D. in Molecular Genetics and the Australian Commonwealth Prize. After an anti-aging lecture tour meeting with MIT professor Dr. Leonard Guarente, David applied to work as a post-grad in his lab and was accepted.

Before long, David brought his passion for fighting time to Harvard University and established a specialized lab to study ways to combat the aging process.

David Sinclair is now a professor in the Department of Genetics and co-director of the Paul F. Glenn Center for the Biology of Aging at Harvard Medical School. He is an inventor on 35 patents and has received more than 35 awards and honors. In 2014, he was on TIME Magazine’s list of the “100 Most Influential People in the World,” and listed as TIME’S Top 50 in healthcare in 2018.

David’s fight against aging hasn’t been easy. It was a rough go from the start. The more Dr. Sinclair asserted the validity of his early findings in the press and medical journals, the more the scientific community was vocally critical of his avenue of research. For years, funding and staffing swung in up and down extremes as his credibility was openly called into question.

Despair and depression set in, as he began to second-guess his entire life’s work.

Then, a funny thing happened. David started to achieve breakthrough results. His study and experimentation of a compound called “resveratrol” was shown in multiple peer-reviewed studies to increase anti-aging compounds during laboratory testing. After years of being derided as a “fraud,” his detractors were forced to eat their words.

Today, after nearly a decade of getting the side-eye from the establishment, Dr. Sinclair and his work have been vindicated. His groundbreaking work battling the aging process is now accepted as mainstream science, and he’s sharing what he knows with the world.

His book Lifespan is a New York Times bestseller. In it, he outlines a comprehensive plan for extending the human lifespan and achieving a quality of life that will make it worthwhile.

To say this was a fascinating conversation would be an understatement. Dr. Sinclair has been leading the anti-aging charge for years, even when nobody believed him. Now that it’s becoming clear he was right all along, he’s leagues ahead of everyone else in the field.

Sound like someone you might want to hear more from? Me too! Join me on Episode 1,004 to learn more about the anti-aging process with Dr. David Sinclair!

The Big Question: Can Humans Ever Become Immortal?

I had one of the world’s foremost geneticists in the studio for a second time, so I knew I had to ask him the big question: Does he think there’s a possibility that humans could ever become immortal? Could science, technology, and medicine ever fully stop the aging process and allow us to live forever?

Short answer: No, but Dr. Sinclair thinks we could significantly expand our lifespans to a couple of centuries or more.

“I think we can live many hundreds of years really well. … I think we’ve got some new technology coming out of the aging field that makes the old stuff, even things just two years ago, look primitive. But immortality is so hard. I mean, we’re fighting entropy…. What we’ve discovered in my lab and some others around the world is that it’s hard to preserve adult living things for a long, long time [but] you can keep them together and functioning for longer.” – Dr. David Sinclair

The truth is, aging is natural. Our bodies weren’t meant to stop aging entirely. But the good news is that we really can dramatically slow down and, in some cases, reverse the aging process. We can live longer, healthier lives than ever before, thanks to new medicine and technology. So if we can’t live forever, what’s the next best thing? What’s the ideal lifespan for humans?

“Well, it’s personal, but I would say I wouldn’t mind living for 200 years. … It’s all about being healthy.” – Dr. David Sinclair

That’s a key idea: It’s all about being healthy. Living longer, lengthening our lifespans, and slowing down the aging process isn’t just about living longer. It’s about living well for longer.

“… When you think about extending lifespan, the important thing is to realize that you don’t live longer in old age, you live longer in a youthful state. … If you have the chance to stay young, why would you want to die? I don’t think anybody who’s healthy and has friends and is enjoying their life says, ‘I want to die tomorrow.’” – Dr. David Sinclair

It’s so important not just to try to live longer but to live well. We want to extend our youthful state — living for centuries in a state of being old and sick, unhealthy, or unhappy would be miserable. Living longer as a healthy, youthful adult is the dream!

“When you think about extending lifespan, you don’t live longer in old age, you live longer in a youthful state.” @davidasinclair  

The Truth About Food

So what are some practical things we can do to live longer? What healthy decisions can we start making today to help ourselves live longer in a healthy, youthful state?

It turns out, fasting occasionally can be one of the best things we can do for our bodies. Of course, it’s important not to go overboard — we need food to survive! But fasting for a day or two at a time can give you some really great health benefits:

“… We are talking about not having three large meals a day. And the way to think about it is not that the food is killing you. What it’s doing is it’s turning off your body’s protective mechanisms against disease. … We know that there are at least three main pathways — and by pathways, I mean biochemical workhorses in ourselves, proteins that do good things — … that are activated when we’re hungry and go to work and tell other parts of the cell to clear out the old stuff.” – Dr. David Sinclair

Dr. Sinclair has done a lot of research on the effects of hunger in his lab. It turns out that when we’re hungry — even if we’ve just skipped a meal — our bodies are actually able to clear a lot of harmful stuff. That means that our immune systems can get stronger, we can fight off more disease, and we get to stay youthful for longer.

I recently did my first four-day fast, and I can tell you that the results were incredible. I originally decided to fast because I’d had some inflammation from past sports injuries, and I wanted just to get rid of it. For four days, I had no food, and I drank water, black coffee, and a little juice. It took several days before I started to heal, but about a week later, sure enough, I felt the inflammation go away. And not only that, but I just felt better. I felt lighter, healthier, and more focused than I did before the fast.

Remember: You should never try fasting without asking your doctor first, especially if you intend to fast for multiple days at a time. But if your doctor gives you the “okay,” think about giving it a try! The science backs it up — fasting has great benefits that can keep you healthy and youthful for longer.

Coronavirus: What Can We Do to Protect Ourselves?

It’s no secret that we’re still in the middle of a disease pandemic, so I wanted to make sure I asked Dr. Sinclair about some of the risks and preventative measures we can all take to protect ourselves. According to Dr. Sinclair, aging is actually a huge deal — an older age means more susceptibility to the virus.

“Aging is your biggest risk. If you’ve been healthy your whole life and done the right things, that’s going to protect you from COVID-19 because a lot of things go wrong as you get older that make you susceptible to the disease. One, for sure, is that your immune system is a lot less resilient.” – Dr. David Sinclair

If we’ve been aging and not taking care of our bodies, we age faster and start to experience the negative health effects — including a weakened immune system. That means that it’s easier for us to catch COVID-19.

So what are some things we can do to boost our immune systems? We’ve already talked about fasting and the positive effects that can have on your health, but what if you’re not able to do that right now? Turns out, boosting your immune system might be simpler than you think:

“If anybody is out of shape or is carrying too much weight, those are the easiest things [to deal with]. [The thing] most likely to work is to lose some of that excess weight and get moving. These things are known to greatly improve your immune system and … lower inflammation.” – Dr. David Sinclair

Exercise — that’s all there is to it! Go for a walk, ride your bike around the neighborhood, or take a swim if you live near an outdoor pool and feel safe enough doing that. Anything you can do to get your body moving is going to help slow the aging process and protect you from the coronavirus.

Why You Should Listen to This David Sinclair Podcast Episode Right Now…

This conversation with Dr. Sinclair was powerful. He has so much knowledge to share with the world, and I’m glad I got to bring him on the podcast a second time. I also want to acknowledge him for the hard work he does. He is putting in the hours in the lab every day to discover new ways to prevent aging and keep ourselves healthy. I’m grateful to him for sharing his knowledge and wisdom with the world, and I look forward to having him back here on The School of Greatness a third time!

Before I sign off, I wanted to share with you something Dr. Sinclair said to me at the end of our conversation today.

“What’s on my mind these days is the word ‘kindness.’ … We’re in a world where there’s too much arguing [and] partisanship, and we’re facing an enemy right now. We’re trying to get through this period of our history, and things are going to get tough. Things are tough for many people already. And I just want everybody to remember — it’s easy to say we’re all in this together, but what I really want to say is … let’s be the best people we can be. And kindness is what comes to mind, and if we can just do that, I think we’re all going to get through this.” – Dr. David Sinclair

Those are inspiring words, and I think they’re true — if we can all remember to be kind and face this pandemic together, we’ll get through it. And I bet we’ll come out the other side stronger and greater than we were before.

Thanks so much for joining me today, guys! If you loved this episode, please share it on Instagram! And tag Dr. Sinclair, @davidsinclairphd, and me, @lewishowes. Share with us your biggest takeaways from the episode — I always love hearing from you!

And don’t forget to check out Dr. Sinclair’s book, Lifespan. It’s full of fascinating information, and I know you’ll enjoy reading it!

Stay healthy, friends, and I’ll talk to you next time!


To Greatness,

Lewis Howes - Signature

Some Questions I Ask:

  • Will humans ever become immortal?
  • What’s the ideal human lifespan? 
  • As science progresses, how will we know the difference between humans and artificial beings?
  • Will artificial intelligence ever surpass human thought?
  • What should we eat to maximize our lifespan?
  • Do aliens exist?

In this episode, you will learn:

  • How scientists are learning to rebuild cells from scratch
  • Why anti-aging is about staying young longer, not extending old age
  • Whether we might ever be able to bring people back from the dead
  • How the brain is the most complex system in the known universe
  • The ideal diet for longevity
  • Why it’s almost a certainty that life exists somewhere else in the universe
  • Plus much more…
Connect with
Dr. David Sinclair

Transcript of this Episode

Music Credits:

Music Credit:

Kaibu by Killercats

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