What to Eat & When to Eat for Longevity: New Science | Lifespan with Dr. David Sinclair - S2, Ep. 3

David Sinclair (0:00)

Biology respects moderation. Just three cycles of a fasting-mimicking diet reduced the biological age of those people on average by 2.5 years. Light resets the brain's clock, and food resets the body's clock. Your body processes food best earlier in the day. No complicated rules, no rigid meal plans. It can be really simple, what happens when we don't ever give the body a break from food. Now, women often ask me, is fasting the same for us as it is for men? Another common question I get is, I've hit a plateau, now what should I do? So here's how I troubleshoot.

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.

Hi, everyone. This is a really great episode. I'm excited to share it with you. There was so much to tell you about fasting that I actually had to split it up into two parts. This was a fun episode to record, and at times it got personal. I'd actually been fasting for three days before filming coincidentally, and I was powering through it, but it really was a lot of information, and you'll see, you'll hear a lot of new things. But I had to ask Marissa to go get me some nuts so I could really keep going. I also show some of my own real-time biometric data, such as blood glucose levels. And I also tackled the big questions for you about fasting, like will you lose muscle if you fast and how to stop that? Will it tank your sex drive? And does your brain actually shut off without snacks? And as always here at Lifespan, we really appreciate you all hitting that subscribe button, and joining also us at lifespan.com where we're building the world's largest longevity community. You'll get notified about new episodes and it really helps us fund medical research into longevity and to make an even better show.

Okay, let's go. Today's episode is part two of calorie restriction and fasting. If part one was about why calorie restriction and fasting work, this part two is about how to make them work for you. In part one, we laid the scientific foundation for why eating less is one of the most powerful tools we have for extending your life. We talked about the difference between calorie restriction and fasting and why our ancient biology is poorly matched to a world of constant food. So definitely check that out if you haven't yet. But of course, understanding the science is only half the story. A key question is, how do you actually use this in real life? How is it even possible?

That's what this episode is about. Today, we're going to get into much more practical advice. We're going to look at chrono-nutrition, the timing of meals, and why your body might handle food very differently in the morning versus late at night. We're going to talk about time-restricted eating and prolonged fasting, what's happening inside your body hour by hour when you stop eating, and why processes like autophagy, your actual recycling of proteins in the body, why this process is just so exciting when it comes to longevity. We're also going to get into things that people often ask me. Will fasting make you lose muscle? Does it affect your hormones and your libido? Does it raise your cortisol? Is it bad for sleep? And most importantly, how do you implement calorie restriction or fasting in a way that's safe, sustainable, and personalized? I'll also share some of my own fasting tips and tricks. It really isn't that hard, and the health payoffs are huge. Many of us aren't necessarily eating too much, we're just eating too often, and often too late in the day as well, something that I do way too often. So here's the thing, your body doesn't just care about what you eat, it cares about when you eat. That's the core of what's called chrono nutrition.

It's the science of syncing meals with your body's internal clocks. One study led by my colleague, Sachin Panda, Andrew, call up a picture of Sachin. He's looking very handsome on that picture there. They studied so-called healthy average Americans, and by healthy, they looked at 156 people ranging from age 21 to 56, a huge BMI range from 19 which is pretty thin to 36 which is obese, and none of these were shift workers. So what did they find?