Fasting as a Path to Longevity: The Facts | Lifespan with Dr. David Sinclair - Season 2, Episode 2

David Sinclair (0:00)

Eat Less Often. I can tell you that calorie restriction puts you in survival mode. There's a study that showed that you can slow down your rate of aging. That translates into a lower chance of mortality of between 10 and 15 percent. There's a lot of people worried about muscle. So what does the science say? The calorie-restricted mice lived about 28 percent longer. LCA, which is a bile acid in the gut, could mimic the anti-aging effects of calorie restriction. They changed the microbiome of the mice, and calorie restriction didn't work anymore.

Welcome to Lifespan, a show where we discuss the cutting-edge science of aging and how to live healthier at any stage of life.

I'm David Sinclair, a scientist and professor working on understanding why we age, and discovering new ways to slow and even reverse the aging process.

On this show, I share an insider's look at the latest from my lab, the field and what's just around the corner.

Hey everyone, welcome back to Lifespan. The team and I went down many different investigative rabbit holes for this episode. One of the most interesting was food marketing and bad nutrition science. And it really made me realize how much of our struggle to keep our weight down is due to marketing, some of which goes back to the early 20th century. So we're gonna talk about that in this show. And during the filming of this episode, I showed one of my most valued books from my collection. And I also shared something that really fascinates me. How a 50,000-year-old Neanderthal toe bone fragment, about the size of a large pea, from a cave in Siberia might actually help explain why some of us gain weight so easily, myself included. I once held this bone in my hand at our Harvard Genetics Department faculty meeting. Professor David Reich, the scientist who sequenced the DNA out of that bone, has a lab just down the hole from mine, and I see his clean lab all the time. Of course, I'm not allowed in there. It would contaminate everything. In this episode, there was so much to cover that I couldn't finish it all in one sitting. It actually took a lot of work. So see if you can spot any cuts in the episode where I have suddenly longer hair. As always, of course, we really appreciate you hitting that subscribe button and joining us at lifespan.com. It helps us fund medical research into longevity and make an even better show. Okay, let's go.

Today, we're talking about a subject that's near and dear to. A lot of people's hearts, we're going to talk about not just what to eat, but actually when to eat. As I travel the world and people ask me about living longer and healthier, there's one question that comes up more than any other. And that is, if there's one thing you can suggest to live a long life, what would it be? And my answer is eat less often. And today we're going to talk about that. We're going to talk about caloric restriction. We're going to talk about new science, about the genes and even some small molecules that our bodies make to mimic caloric restriction. We're going to talk about the diets in our ancestry, even going back millions of years that have influenced our genes. Why today's society and how we eat is really so bad for us. And how can we each individually know and learn what's good for us and what will make us live longer? So here at the Lifespan podcast, we aim to be 100% science based and accurate. Our producer and researchers have done a great job figuring out what is real and what isn't. We're going to really talk about that. And of course, there's extensive show notes so you can check our facts that we're telling you today. There's just so much to cover and I can't wait to get into it. Now, first of all, just a little thought about caloric restriction and fasting. They're not the same thing, but they're overlapping. So caloric restriction, by definition, is overall reducing the amount of calories you take in. And fasting is eating less often, usually in a certain time window. But they both have very similar effects. The kind of things that you see, especially in animals and now in some human studies, include things like lower blood pressure, of course, lower body weight, better memory, more energy. There's a study that showed that you can slow down your rate of aging by about 2 or 3 percent. And while that may not sound like much, that translates into a lower chance of mortality of between 10 and 15 percent, which is dramatic. And so this diet calorie restriction is actually the strongest, most potent, most reproducible way to extend the lifespan of animals and probably ourselves as well, at least until we develop drugs that mimic this diet even more accurately. Before we dive in, I want to give you a quick glimpse of where we're headed. So Andrew has pulled up on the screen a roadmap, a step-by-step way to implement fasting or calorie restriction safely and effectively. I'll walk you through this later from figuring out your what and why, to choosing the right strategy, to what to monitor and how to adjust things as you go. The majority of us are overweight and at least about 30 percent of us in the United States are obese.