Super Human. Dave Asprey

is to assess its stability. Oxygen drives very strong chemical reactions that damage fats through oxidation. Oxidized (damaged) fats cause you to age more quickly by creating inflammation in the body and building less effective cell membranes. When your body has no choice but to incorporate oxidized fats into cell membranes, those cells create excess free radicals that make you an average human, not super.

      Your cells use saturated fats, which are the most stable of the fats, to make about 45 percent of the cell membranes in the brain and liver, and about 35 percent in heart and muscle cells.¹⁹ Yes, saturated fat is the dominant fat in your brain, so don’t demonize it! Energy-producing cells will hold their level of saturated fat at about this level no matter what type of fat you eat. The only type of tissue that meaningfully changes its composition of saturated fat is adipose tissue—aka your muffin top. When you eat more saturated fats, the cells in adipose tissue will change their makeup to contain more saturated fat and less unstable fats without changing in size. This is fantastic, as stable fats make for fewer free radicals.

      Think of saturated fat as the stable waxy bricks building the “walls” for your cells. The problem is that your cell membranes have to flex in order to make energy and receive chemical signals, and those nice stable saturated fat “bricks” don’t bend. So while it’s fine to go ahead and eat butter and other forms of saturated fat, it’s also important to eat other types of fats. And those include the next most stable group of fats, monounsaturated fats. These fats—found in food sources like olive oil, avocados, and some nuts—are more flexible than saturated fats. You can think of them as the gel-like “mortar” that supports your saturated fat bricks in the cell wall. Your cell membranes are made up of about 20 percent monounsaturated fat.

      Interestingly, brain cells have the most monounsaturated fat of any cells in the body, and they hold their level of monounsaturated fat constant no matter what types of fat you eat. Most other cells adjust their fat content slightly when you eat a lot of monounsaturated fats. But without changing how much fat you have on your body, fat cells will happily dump other stored fats and replace them with monounsaturated fat. This means you can transform your stored body fat to have a higher percentage of stable fats. Eat your olive oil!

      After you account for the saturated and monounsaturated fats in the membranes of energy-producing cells like muscle, you’re left with about 35 percent of a combination of polyunsaturated omega-6 and omega-3 fats, as well as some conjugated linoleic acid (CLA), a type of fat produced by microbes in your gut. (CLA also happens to be found in grass-fed butter—more on this in a bit.) While omega-3 and omega-6 fats fall under the same category, they are not the same.

      Omega-3s are anti-inflammatory and thus beneficial to your anti-aging efforts. The best omega-3 fats are found in food sources like cold-water fish (salmon, mackerel). You can also get omega-3s from walnuts and olive oil, but vegetable omega-3s are only 15 percent as effective as those found in fish.²⁰

      Unfortunately, omega-3 fats are far outnumbered by omega-6s in the standard Western diet—and omega-6 fats are highly inflammatory. Poultry, the most common protein in Western diets, is high in omega-6s. Most refined vegetable oils are also polyunsaturated omega-6s, and they are so unstable and inflammatory that eating excess canola, corn, cottonseed, peanut, safflower, soybean, sunflower, and all other vegetable oils is likely to contribute to cancer and metabolic problems. Oxidized omega-6 fats damage your DNA, inflame your heart tissues, raise your risk of several types of cancer, and don’t support optimal brain metabolism.²¹ Anything that increases inflammation decreases brain function.

      When you cook with those fats, they are even more aging because they become oxidized so easily. Remember how aging oxidative stress is? Eating oxidized fats speeds this process way up. Additionally, trans fats are a category of omega-6 fats that are the most dangerous of all. Decades ago, when food manufacturers needed a shelf-stable fat for processed foods, they created hydrogenated omega-6s, or trans fats. These fats are linked to many health problems and cause obesity, and it took the food industry only forty years from the time they learned about this to begin phasing them out. When you ingest man-made trans fats, your body tries to use them to build cells, but cell membranes made of these trans fats cannot function properly. And without healthy membranes, you’ll never make it to a hundred and eighty—or even a comfortable seventy-five.

      Artificial trans fats also form when you use polyunsaturated fats for frying.²² Fortunately, trans fats won’t likely cause problems if you use the oil for frying only once, but restaurants often use the same oil over and over all day or all week, which creates oxidized oil and trans fats. So put down the French fries, no matter how lean you are. Seriously—you’re better off having some rum or smoking a cigar. Super Humans don’t eat fried food, even if it’s crispy and delicious. You know what’s not delicious? Eating from a tube later because you couldn’t put down the chicken wings when you were younger.

      Your body does need some omega-6s, but there are so many of them in a standard Western diet that you would have to work really hard to consume too few. Ideally, you should consume no more than four times as many omega-6s as omega-3s, but most people today eat an average of twenty to fifty times more omega-6s than omega-3s. This is a hugely underreported source of accelerated aging. Changing the balance of omega-3s to omega-6s you consume can give you a Super Human metabolism because your stored fat cells change dramatically when you eat omega-6 fats. No matter how much (or how little) body fat you have, anywhere from 7 percent to 55 percent of it is made of inflammatory omega-6 fat, depending solely on how much of each type of fat you eat.

      If you are lean, you want to eat the same composition of fats that you want stored in your body. That means that whether you’re on the high-fat Bulletproof Diet or a low-fat diet, stick to about 50 percent saturated, 25 percent monounsaturated, 15 to 20 percent undamaged (meaning not oxidized) omega-6, and 5 to 10 percent omega-3 fats, including EPA and DHA. If you are obese and have a good amount of excess body fat (like I used to have!), right now your body is probably storing too many unstable fats. To shift your fat composition, temporarily eat an even higher percentage of the type of fats you want in your body. Of the fat you eat, 50 to 70 percent should be saturated, 25 to 30 percent monounsaturated, and only 10 percent undamaged omega-3 and omega-6.

      The challenging thing is that the most common blood tests doctors use to measure things like cholesterol and triglyceride levels do not offer an accurate picture of the type of fats in your brain, heart, or muscle cells, which is different than fat in your blood cells. So there is good reason to distrust the fat ratios found in the blood tests that most doctors rely on. Looking at inflammation markers in your blood work, such as C-reactive protein (CRP) and homocysteine, will give you a much more accurate sense of how you’re aging.

      When I started experimenting with eating more fat, I was nervous—it went against everything I’d been told about healthy eating. One of the biggest leaps I took was to begin eating more grass-fed butter. When I took a deep breath and stopped holding back on butter, magical things started to happen. My focus increased, I had more energy, and my blood panels showed that my levels of inflammation had decreased.

      Like any good biohacker, I kept experimenting until I knew I had taken things too far. I heard that some Inuit populations survived on no carbohydrates at all, so I decided to subsist on a diet of almost entirely fat and animal protein and see what it would do for my health and performance. The result of that experiment was a host of new food allergies because the bacteria in my gut were literally starving and out of desperation began eating my own gut lining. Sadly, a diet of only steak and butter won’t work for the long term. But it was delicious in the short term.

      PIG’S EARS AND ENERGY FATS

      By implementing everything I’d learned about nutrition, I was able to dramatically decelerate my aging. My knees were still a mess, but I weighed less and had more energy than ever before, and I managed to (barely) graduate from business school while working full time despite my cognitive dysfunction. I decided to celebrate with a trip to Tibet to learn meditation from the masters there, something I never would have been able to do when I was old, obese, and inflamed because it involved a lot of hiking and steep terrain.

      I had just descended 7,500 vertical feet in one day in Nepal when I knew there was