Caloric Restriction Deep-Dive & Longevity Secrets of Long-Lived Animals | Dr. Steven Austad

Live Longer World Podcast #25

"I can tell you, people cannot calorically restrict like we do mice. It's a rare, rare person that can do that. Anybody almost, I think, could say, "Okay, I'm going to do my eating between 11 in the morning and 6 at night or at 8 at night or something. Almost anybody could do that. If that is a way of controlling calories, maybe that just prevents obesity, whatever, people can do it. If it helps people maintain a healthy body weight, that's great."

Live Longer World Podcast #25 has been released!

My guest today is Dr. Steven Austad. He is a professor in the Healthy Aging department at the University of Alabama and also scientific director of the American Federation for Aging research.

He has a fascinating entry into the world of aging research - it all began with training lions!

There are many open questions on the caloric restriction research for enhancing longevity and we dive into that. Further, a lot of Dr. Austad’s work focuses on what long-lived animal species can teach us about living longer and healthier lives. His lab works on exotic species, like clams that live more than 500 years, and hydra that don’t age at all, in order to discover aging treatments. He also tries to uncover the mysteries around why men and women respond differently to longevity therapeutics.

Dr. Austad is also a writer and has written several books including Methuselah’s Zoo: What Nature Can Teach Us About Living Longer, Healthier Lives and his latest book To Err is Human, To Admit It Is Not.

[If you are a premium subscriber, you can also read the transcript of the episode below]

Best, Aastha

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Time Stamps:

0:00 Training lions

7:15 Learning from Long-lived species

9:55 Bowhead whales live 200 years

12:55 House sparrows & longevity

14:40 Study "successful" animals

18:10 Naked Mole Rats

20:45 What do bowhead whales die from?

26:05 Why do ocean animals live longest?

31:05 Beyond Caloric Restriction

36:00 Intermittent Fasting & Circadian Rhythm

42:40 Caloric Restriction for Healthy people?

46:24 Will coffee shorten your life?

49:43 The Blue Zone Myth

55:50 Young Blood, I can't get you of out my Mind

1:00:26 Hormones & Health (Growth Hormones for longevity?)

1:05:18 Sex differences in longevity

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Premium Subscriber Transcript:

[00:00:02] Aastha Jain: Hi, Dr. Austad, welcome to the Live Longer World podcast.

[00:00:06] Dr. Steven Austad: Thank you, it's a pleasure to be here.

[00:00:08] Aastha Jain: I'm very excited to talk to you, not just because of your research in aging and your unique perspective on looking at longer-lived animals, but I think you also have a very unique backstory on how you got into aging research. I'd love to start there. I'm sure you get asked this story multiple times, but it's hilarious and mind-blowing.

[00:00:30] Dr. Steven Austad: Sure. Well, there are two backstories really. There's one about how I got into science, and there's one about how I got into aging research. Aging research really started on-- I was in South America, I was in Venezuela working on some birds there, wasn't interested in longevity at all. A friend of mine was trying to study foxes, but he was having no luck because he kept getting his traps filled up with opossums. Now, these are very similar opossums to the ones that occur in the US. They're not the same species, but most people would not be able to tell them apart. Again, I said to him, "You idiot, you're working on the wrong project, you should be studying these opossums."

He said, "Well, what can we do with them that would be interesting?" We came up with a project, had nothing to do with aging. Part of that project meant that I had to go out and I had to capture them every month. I had radio collars on them. If they died, I could tell that they had died because I had a switch on the radio collar that would change its frequency when they stop moving. What I discovered by accident is that they aged incredibly fast. I would catch one that was a vigorous, young adult. I would catch it two or three months later, and it would have cataracts, and its muscles would have shrunk, and it would have parasites, and just be a mess.

That observation attracted my attention far more than the project that I was actually working on. By the time I finally published the project that I was working on, I'd lost interest in it entirely. I was interested now in why they're aging so quickly. I'd assumed that they would age like a house cat because they're the size of a house cat, but they didn't. They aged so much more quickly. That observation has kept me interested now for over 30 years in trying to understand why different animals age at different rates, and is there any lesson that we can learn from them about making us age at a slower rate, possibly?

[00:02:54] Aastha Jain: That's exactly what I want to dive into. Maybe, backstory even before that, how did you get into science? That involves some lions being driven in your car.

[00:03:05] Dr. Steven Austad: I was an English major as an undergraduate. I wasn't at all interested in science. The only science course I took was, we call it microbiology for poets. The closest we got to a laboratory is that the professor wore a laboratory coat when he was lecturing for some reason, I don't know. Anyway, I did a variety of odd jobs while I was writing the Great American Novel. Since you've never heard of the Great American Novel that I wrote, you can see how well that went.

Eventually, I found a job by accident training lions for the movie business. I didn't know anything about them when I got into it. It was a sheer accident. I got hired. I told the movie producer I don't know anything about lions. He said, "That's okay, I've hired people who you can learn from." I did that for three and a half years. It awakened my interest in what made animals tick. Most of the time, I spent trying to keep the animals from killing me, that was one way that animals tick that I was interested in. That really awakened my interest in biology.

When I decided I didn't want to do that for the rest of my life because, believe me, the Hollywood crowd is a really boring crowd to be around. They may be celebrities, but by and large, they're not very interesting people. When I decided I didn't want to do this for the rest of my life, I thought I'll go back to school, I'll learn a little bit of science, and try to study animal behavior in a more systematic and rigorous sense. That's what I did.

In fact, I went to graduate school with the aim of studying lion behavior in the wild. Early on in my graduate career, I went over to East Africa, to the Serengeti where a lion project had just wrapped up, thinking I might take it over. In the interim between the time I heard about it and the time I got there, someone else had already taken it over, so that didn't work out. I came back and switched to something very, very different. I was actually interested in how animal combat behavior evolves because I'd broken up a lot of lion fights, so I knew a lot about animal combat. That's what I did my PhD on.

It's really animal behavior that I was interested in. Then, I got exposed to aging. That just struck me. I think because everything else I did, as soon as I felt like I had it figured it out, I'd lose interest in it. Aging, I don't think I've ever quite figured out, so it's maintained my interest.

[00:06:01] Aastha Jain: I think you see that a lot with people who are attracted to the aging field. Sometimes, they just get bored of all the easy things, and they want to move on to the ambitious things. Aging, there's just so much yet to be figured out. There's so much you can keep learning and keep discovering, which is fascinating.

[00:06:17] Dr. Steven Austad: Right, which is fun. Suddenly, you're interested in the immune system, so you have to learn all about the immune system. It's great, really is.

[00:06:27] Aastha Jain: Yes. Then, you started doing fieldwork. Obviously, your background was also just studying animals. That's how you got interested in studying long-lived animals, the story you told us about opossums. Maybe, tell us about what you've learned studying some of these long-lived animals, maybe some examples of just different animal species.

[00:06:49] Dr. Steven Austad: Well, I think one of the things that I've learned, and I don't think we knew this a while ago, is that there are many ways to be long-lived. There's not just one magic thing that all long-lived animals share. Some of them, it's because they can maintain their cellular energy balance. Sometimes, it's that they are better at maintaining their proteome. Sometimes, it's just because they live a very, very slow life.

That's probably not the kind of long life that humans are interested in. I've been thinking a lot recently about giant tortoises. Giant tortoises can live over 150 years for sure, maybe as long as 190 years or so. They do that by living extremely slow lives. Their heart beats at six beats a minute. When they're sprinting, they're covering about 200 meters a day if they go 24 hours a day. That's a long life, but it's probably not the kind of long life that most people envision for themselves.

[00:08:05] Aastha Jain: I also feel like, wouldn't it have the opposite effect on humans? If we're just living such slow-- I guess there's one aspect of you're living a completely stress-free life, but then the other aspect is if you're not moving at all, you're not exercising, we know that's not good for us.

[00:08:21] Dr. Steven Austad: Right. The world would seem to move so slowly. If we could, for instance, go into some suspended animation and live a thousand years because we're locked up frozen in a box, that's a long life, but I don't think it's the kind of long life that people care about. We want to be active, and vigorous, and healthy for a long time. What that's taught me is that there are really animals that live a long time that are less interesting, and animals that live a long time that are more interesting. More interesting because the way they do it might seem more applicable to the longer, healthier life that humans aspire to.

[00:09:06] Aastha Jain: Can you talk about some of those animals, the more interesting ones that you can learn from?

[00:09:10] Dr. Steven Austad: Yes. Well, let me just compare two that live a very, very long time but in a different way. There is a whale species called the bowhead whale that is estimated to live over 200 years. Now, you might think, well, that's very, very different. It's the whale that lives in the coldest water anywhere. In fact, they protect themselves from predators by going under the ice where they can still break through and their predators like killer whales cannot do that, so it's a way to escape.

Here's the interesting thing about them. Unlike cold-blooded animals like the giant tortoise. Giant tortoise, the colder it is, the slower everything moves. With mammals, it's the opposite. The colder you get, the more your metabolism kicks up. When we now know that bowhead whales have about three times the metabolism that we previously thought they did. They're not a slow animal at all. They're a fast-living animal, but they live 200 years. How do they do that? We don't know a lot about that yet. It's early days.