There's about 100 cases in the peer-reviewed literature where doctors think 'Aha, here's somebody who's got [COVID-19] a second time.' 100. Now, we're talking 100 out of 8 billion people on Earth. They think there's 100 cases. I've looked at every one of them, and every one of them is basically just another exercise in false positive testing.

The benefits of an infrared sauna compared to a dry sauna

Are ketone esters or exogenous ketones these magic drinks that make you melt fat off your body? The answer is no. These are calorie-containing substances. If you have an energy surplus or a calorie surplus, ketones aren't some magic thing that break the second law of thermodynamics that [makes calories disappear]. But, that doesn't say that there aren't appetite-controlling effects that are second-order from just the calories themselves.

Nothing has given me more mental confidence than being able to go straight from room temperature into the cold.

The consumption of coffee, particularly one cup a day, is associated with a 12% lower mortality risk, and then two or more cups of coffee a day—a 41% reduced risk of mortality.

Jack Dorsey's daily routine

If COVID could be magically transmitted by people with no symptoms, it would be the first respiratory illness in the history of medicine where that's the case.

What is a ketone salt? It's simply beta-hydroxybutyrate bound to a mineral—a salt. A lot of common ketone salts are sodium, magnesium, calcium ... Pros: relatively cheap, relatively available. [One] potential con is that if you actually look at the percentage of salt versus beta-hydroxybutyrate, you're eating a lot of mineral ... If you look at the label, oftentimes you're seeing like 200% of your daily recommended value for salt.

If you're finding yourself reliant upon those compounds [nootropics and smart drugs], in my opinion, you need to back off and dial in your sleep and your energy levels.

The standard advice to eat less and move more doesn’t work. We all know it, and the studies all show that it doesn't work. So, why shouldn't we use this tool that we have [fasting], which is honestly the most powerful weight loss tool? Because you cannot go lower than zero calories ... This is the most powerful tool, and we’ve decided to not use it? Are you kidding me? That's gotta be the craziest thing I’ve ever heard.

The amount of weight loss, the amount of fat loss, [while] fasting only averages half a pound of fat per day ... So, on a 7-day fast, which sounds really extreme, you can expect to lose 3.5 lbs of fat. That's it.

Jack Dorsey tells the story of how he got over a speech impediment

The best single metric I use that I actually optimize my training for is what's known as a 2-minute recovery ... You take your body to as intense an exercise as you can tolerate and then stop, and then you see how fast and how strongly your heart rate recovers after 2 minutes. If you knew nothing else about somebody but what their 2-minute recovery was, you could predict a lot about their health, not just their fitness.

One study at Oxford University on over 80,000 people found that those who play racket sports, like tennis or racquetball, on a regular basis reduce their risk of dying prematurely by over 47% percent. The next most beneficial exercise turns out to be swimming, which reduces the risk of dying by 28%.

Forward movement or forward progress—whether it's riding a bike, or whether it's running, or whether it's walking, or anything that's convincing your brain that you're progressing forward—is actually a pretty cool remedy for fear, or stress, or anxiety, or depression because you literally suppress the section of the amygdala responsible for those hardwired responses, and you secrete dopamine when you're stepping forward.

In flies and worms, just a brief exposure to heat treatment has been shown to increase their lifespan by up to 15%—and that's mediated by these heat shock proteins. That hormetic response that increases the heat shock proteins is associated with longevity, and it's just basically decreasing the rate at which telomeres shorten. It's protecting DNA, cellular membranes, and mitochondria when you have this regular sauna practice.

These are things that we have to watch out for. If you're going to try to use modafinil for cognitive enhancement, specifically with the goal of restricting your sleep, you will pay a physiological price for that.

When you train in a fasted state, you really do get a lot more of a benefit in terms of fat loss

If you look, historically, at hunter-gatherer diets, they tend to be, when it comes to omega-6 to omega-3 fatty acid ratios, typically somewhere around 2-1 to 4-1. Our modern Western diet tends to be 20-1 up to 50-1 in favor of omega-6 fatty acids.

There's another omega-3 fatty acid called alpha linoleic acid (ALA)—that's a plant-based omega-3 fatty acid, and even though people will turn to things like chia seeds or flax seeds to try and get that ALA, the conversion is remarkably poor. You could make an argument that you can get a decent amount from algae sources, like spirulina and chlorella, but they still don't touch the small cold water fish with a 10-foot pole when it comes to the actual availability of the omega-3 fatty acids.