In the first article in this series on longevity, I talked about why hormesis is the most important concept in longevity science.
In sum, when it comes to living longer, what doesn’t kill us, makes us stronger.
Some level of stress is absolutely necessary to live our best life, and now we know that it’s needed to live our longest life also.
When it comes to nutrition, there’s specific longevity research in a few areas, and sometimes it’s challenging to distinguish between them, because they go hand in hand.
Today let’s look at each of these, and how they impact our health and longevity. The goal is not to do all of these perfectly, of course. If you want to live a longer, healthier life, it’s about finding a routine that works best for you.
That may involve adding intermittent fasting, or it may involve cutting back on your animal protein intake.
If you do decide to give one of these a try, start with just one change at a time.
Habits take time to shift. Trying to adjust a lot at once is a recipe to ultimately change nothing at all.
As we touched on in the hormesis article, there are 3 main mechanisms that are well-researched for longevity.
mTOR – Less mTOR activity = longevity. Less protein, in particular leucine, turns off mTOR.
AMPK – More AMPK activation = longevity. Lower blood sugar, higher AMPK
SIRtuins – More SIRtuins = healthier DNA. Many interventions increase SIRtuin activity. When cells are stressed, they often increase SIRtuin activity, hence hormesis.
Nutrition, in various ways, plays a role in all of these. Let’s dive into how we can adjust our nutrition to live longer and healthier.
Note: Dietary changes like IF, caloric restriction, and adjusting protein intake are not to be done lightly. Please do so in conjunction with your health care provider and please do not do anything stupid that would make us both upset. You’ve been warned, dear reader.
Damn, is there anything intermittent fasting can’t help with? We have extensive guides on intermittent fasting for fat loss, but when those were written nearly a decade ago, intermittent fasting for longevity was undiscussed terrain.
When we go back to our understanding of hormesis and longevity, it makes perfect sense why periods of fasting would improve longevity.
A length of time without food will definitely turn off the mTOR pathway and reduce blood sugar, which activates the AMPK pathway.
It can also boost sirtuin activity (and increase NAD levels which decline with age), as has been shown in several studies.
IF is one of the clearest interventions for longevity, but it still brings up a lot of questions.
For example, is it the IF itself, or the fact that fasting corresponds to lower caloric intake?
The answer, per the research, is both.
Intermittent fasting on its own will kick-in our body’s natural defenses.
As Dr. David Sinclair writes in his book Lifespan, “This makes sense. It engages the survival circuit, telling longevity genes to do what they have been doing since primordial times; boost cellular defense, keep organs alive during times of adversity, ward off disease and deterioration, minimize epigenetic change, and slow down aging.”
The next obvious question is for how long.
A lot of the specific research is on 16 hour fasting. For example, this often cited 2012 study on mice allowed one group to eat whenever they wanted, and the other to only eat 8 hours a day. The group with the restricted feeding window lived longer.
But this seems relatively arbitrary. This 2021 study in the prestigious journal Nature saw benefits from IF ranging from 12 hours to 48 hours.
That study also saw benefits to longer-term fasts.
Based on the current research, fasting for 20 hours is probably better than 16, which is better than 12, which is better than 8.
But there are practical considerations here.
For example, competitive athletes, in order to properly fuel for competition and training, may struggle with a 16/8 fasting. But, maybe 12/12 will work fine. This may especially be valuable for older athletes who want to lengthen their careers and prevent decline. However, this area hasn’t been researched specifically, so it’s all anecdotal experiments.
Personally, because of my routines and social life, I try to eat an early dinner, and shoot for 16 hours, but if I eat dinner at a normal time, around 8pm, I’ll still aim for 12 hours every day.
Even when I go out, I’ll try to wrap up drinks before midnight, and then fast for 12 hours.
More and more research will come out, but I don’t think we need to overthink it.
A cousin of intermittent fasting, caloric restriction, independent of fasting, has also shown benefits for longevity.
And it also has impressive research behind it, such as this 2017 study published in Nature, which examined a breadth of literature on caloric restriction and longevity.
Again, restricting calories generally will reduce mTOR activity, increase AMPK activity, and increase SIRtuin activity.
There’s also a ton of corollary data that places we people eat fewer calories overall, tend to live longer.
Often, this goes hand in hand with intermittent fasting, and it’s partially why IF is so effective for weight loss.
When you restrict your feeding window, you tend to eat fewer calories.
If you’re thinking about trying this, keep in mind that a lot of the research has looked at a 20-50% reduction, at least in animals.
If you’ve never tracked calories before, you should know that this is a lot. All of the sudden slashing your calories in half is a terrible idea.
First, you’ll want to know how many calories you’re eating. That’s obvious. From there, slowly aim to reduce calories by 5% per month. This is very conservative. If you eat a 2000-calorie diet, getting to a 20% reduction, 1600 calories, will take 4 months.
This isn’t a “get fit in six weeks” strategy. This is a forever game.
You’ll also want to track your performance in the gym or otherwise. Caloric restriction might not really be what you want. Especially if you’ve never tracked macros before.
Unless you’re already an experienced macro-tracker and dieter, I’d personally suggest looking elsewhere for longevity interventions.
It’s just… a lot of work with unclear protocols for what works.
The other reason I’m not a huge fan of CR is because it appears to not work in every case. In one study, ⅓ of mice saw no benefit.
Again, on a practical level, I don’t recommend it.
Now, what I do recommend, generally, is to eat slower. And I… personally am terrible at this. But people who eat slower tend to consume fewer calories and have better digestion. So that’s another to apply the benefits of caloric restriction in a more sustainable way.
A hormone called ghrelin is responsible for how hungry we feel. Some research has suggested that ghrelin is partly responsible for the longevity mechanisms to take full effect.
So if you’re a little bit hungry while doing IF, that’s okay. In fact, it may be part of the process.
This is the one that throws the meatheads among us for a loop.
And for this part, we’re focusing on the longevity pathway known as “mTOR.”
In our cells, the mTOR mechanism can either be “on,” or “off.” When it’s on, it encourages cell growth. When it’s off, it encourages our cells to conserve and recycle.
mTOR is regulated by the presence of amino acids in our bloodstream. In particular, by the essential amino acid leucine, which is abundant in animal proteins.
When we have a nice big steak, it signals to our body that times are good, that we don’t need to conserve our resources.
To improve the overall health of our cells and live longer, we want mTOR to be turned off sometimes.
When mTOR is off, our cells will boost their defenses and recycle proteins. As Sinclair writes, “When our ancestors were unsuccessful in bringing down a wooly mammoth and had to survive on meager rations of protein, it was the shutting down of mTOR that permitted them to survive.”
We have been taught, correctly, that turning ON mTOR is essential for building muscle. This is why animal proteins may be more effective for building muscle. They have higher concentrations of leucine.
Obviously, mTOR being on sometimes isn’t going to kill us. But striving to always turn on mTOR by eating a ton of protein all the time, might.
There are a few ways to limit mTOR activation.
First, intermittent fasting will keep it off for some of the time.
Longevity and plant-based diets seem to go together very well. Populations that eat less meat, unsurprisingly, tend to live longer. This is probably at least partly because they’re not activating mTOR all of the time because plant based diets eat less protein overall.
Of course, we need protein, and this goes against the most basic of health, fitness, and fat loss advice.
Instead of suggesting you eat less protein, I encourage you to eat more plants.
As a by-product, you may switch out protein packed sausage for lunch for a salad with nuts, olive oil, and even a bit of meat, if you’d like.
It’s not hard to see why that kind of choice will make you live longer.
Plant proteins have fewer BCCAs, including leucine. So with plant-based protein sources, you can have an abundance of protein that can still support your muscles and performance without activating mTOR.
Yes, I know, a lot of vegan protein powders taste all chalky, but there are a LOT out there that taste fantastic and mix easily.
I’m not suggesting your switch to veganism, although if you’re drawn to that I support it.
Personally, I’m eating less meat because of the ethics, effects on the environment, and yes, because I’m trying to live to see what iteration of civilization comes after the nation state.
A lot of BCAA’s benefits are marketing hype, anyway. It’s generally overrated for muscle growth and recovery, and it’s definitely going to activate mTOR.
It’s a supplement almost all of us can go without.
Sugar is bad. I’m not going to get into this too much. Limit processed foods and alcohol blahblahblah.
Another reason these foods are cutting our lifespan is because spikes in blood sugar turn off AMPK.
In general you want to keep your blood sugar steady.
There’s a lot to say about this, and ways to go about it, but one exciting way to look at this is to look into continuous glucose monitors, which track your blood sugar in real-time.
They used to only be available for people with diabetes, but the technology has come a long way. In 3-5 years, I suspect 24/7 glucose monitoring will be like having an Apple Watch or Oura Ring.
In the meantime, watch your processed carbohydrate intake.
Again, I don’t want to say for the thousandth time what you’ve heard, so I’ll keep this specifically to longevity research.
Dr. David Sinclair has coined the term xenohormesis, which is the idea that we should eat stressed foods. Many fruits and vegetables have developed their healthy attributes in response to the stress they endure (hormesis).
The practical rule that I’ve adopted for this is two-fold:
I would say between this alone I get about 6 servings of fruits and vegetables. They say to aim for 10, and with 6 as a bare minimum, I’m in a good spot.
My other secret, if I may offer one, is hummus. Name a vegetable that doesn’t magically taste good with hummus. When I’m craving a snack, I turn to hummus with carrots, cucumbers, peppers, and more.
This is NOT a workout program or diet where you have to change everything at once. These are all habits that you can change slowly over time. And some of these, you may never adopt, and that’s totally fine.
This is a forever thing.
Whether it’s just implementing a few more hours of fasting, switching up your protein sources, adding a salad for lunch, little changes compounded over time can have big effects on our health.
Some of these, like intermittent fasting and protein restriction, have a reputation for reducing performance. Yes, of course, they can.
But if you make changes slowly and don’t go to extremes, I’ve seen in many cases that, practically speaking, it doesn’t at all.
In fact, I’ve been in the best shape of my life after adapting rules around eating more veggies, maintaining consistent feeding windows, and swapping out some protein sources.