Dave Asprey - Super Human - The Bulletproof Plan to Age Backward and Maybe Even Live Forever

One last time: Your body requires fats for you to perform your best and live as long as possible. You just have to know which fats serve what purpose. Some fats you eat are building blocks for your body, and some are better used as fuel. Getting the mix right matters. But have you ever heard nutrition “experts” say exactly which of the many saturated (or other) fats to avoid? The typical buckets you hear (“plant based,” “animal fats,” “saturated,” “polyunsaturated”) are not very specific. Is it possible that the heated industrial polyunsaturated fat in French fries has a different effect on your biology than avocado oil, or that the fat in industrially-raised animals is different from the fat in an egg yolk or pastured beef? You bet it is.

Researchers in Australia have measured how different cells elegantly use each type of fat you eat. You can make sure your brain has the type of fuel it runs best on and that your body fat doesn’t create extra inflammation and make you old. Eating the right fats could add productive years to your life, which is why it’s worth a page or two of your time to dig a little deeper into details of how your body uses fats.

Scientists describe cell membranes as “the margin between life and death for individual cells.” 17These membranes are made of tiny droplets of fat. About 5 percent of your genes contain instructions telling your cells how to make the thousands of types of fat your body needs to survive. We now know so much about what each different type of fat does that French researchers have proposed the notion that “saturated fats should no longer be considered as a single group in terms of structure, metabolism, and functions.” 18In other words, we have grouped together a very diverse array of fats under one reductive and often misleading label. When your doctor tells you to eat less saturated fat, your response should be “Which one(s) do you mean?”

I’ve had the opportunity to interview lots of fat experts (or experts on fat), and most of us use an analogy from nutritionist and early trans fat researcher Mary Enig, PhD, who popularized two basic ways of thinking about the fat you eat. The first is to look at how long a fat molecule is. There are short-chain, medium-chain, and long-chain fats. As a general rule, the shorter the saturated fat, the more anti-inflammatory it is. For instance, butyric acid, which is anti-inflammatory, has only six molecules, while other types of fat may have twenty or more.

Some fats are easy to damage no matter how long they are. So the second way to understand your fat 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. 19Yes, 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. 21Anything 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. 22Fortunately, 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.