Why you should be eating liver and drinking bone broth.

For maximum health, it pays to go deep. This means satisfying the nutritional needs of our DNA with natural foods raised sustainably and humanely, and prepared in traditional ways, explains Catherine Shanahan, M.D., co-author of “Deep Nutrition: Why Your Genes Need Traditional Food” (Flatiron Books). These foods are richer in nutrients than modern, factory-produced ones, which are often toxic. “It’s about connecting our bodies on the microscopic level with the ecosystem,” she says.

Read on to learn Shanahan’s secrets for incorporating what she calls “The Human Diet” and the “Four Pillars of World Cuisine” into our lives.

Become a conscious consumer

“There are vast differences in food quality at the grocery store,” Shanahan explains. She recommends investing in grass-fed or pasture-raised animal products and organically- or bio-dynamically-grown produce since—thanks to richer soil—they will possess more nutrients. If fish and animals are fed their natural diet (for instance, grass for cows and plankton for some fish), they won’t get sick as often and, as a result, will not need to be dosed with antibiotics. And, if crops are grown organically, they will not contain toxic pesticides.

Eat the whole animal—including the organs

Sure, animal flesh (muscle) is full of nutrients. But, don’t overlook the organs. They’re rich in vitamins and minerals, says Shanahan, and each one bio-concentrates a different blend. For instance, the liver supplies iron and B-vitamins; the kidneys Vitamin-A and folate; and the brain Vitamin B12, phosphorus and selenium. For many of the same nutrients, reach for omega-3 eggs (especially the yolks) if you are truly averse to offal, counsels Shanahan.

Bone up

Thanks to their collagen, calcium and glucosamine, bones and cartilage promote bone, joint and skin health (collagen even helps reduce cellulite), says Shanahan, who serves as director of the Los Angeles Lakers Pro Nutrition Program. She swears that bone broth is one of the NBA’s secrets. “We’re getting a lot of players to have soups that are made with bone stock, and it’s really great for their joints. It’s like this magic formula. It actually has a growth factor-like effect on the collagen, which is the backbone of your skin and joints,” she says. If you can’t consume meat-on-the-bone or bone broth, Shanahan recommends taking collagen supplements.

Cook meat in traditional ways

Since overcooking meat robs it of nutrients, handle it gently. If you sear or grill, make sure the inside remains moist. Ideally, cook tough cuts of meat-on-the-bone in liquid, so their connective tissues break down, enriching soups and sauces with nutrients and flavor.

Choose dairy produced from grass-fed animals

You’ll glean minerals in high concentrations, says Shanahan, who recommends raw, whole milk (if you have a good source) and organic yogurt.

Natural, unrefined fats are your friend

If produced from grass-fed animals, animal fats (including dairy) will supply your body with omega-3 fatty acids, conjugated linoleic acid (CLA) and fat-soluble vitamins, such as Vitamin K2, points out Shanahan. If you’re worried about cholesterol and heart attacks, she explains that “saturated fat does not oxidize spontaneously in our arteries the way sugar and polyunsaturated fats can. There is no biochemical mechanism by which saturated fat can play a role in heart attacks.” Shanahan also champions unrefined, low-polyunsaturated-fat oils (olive, avocado, peanut, coconut, almond, macadamia nut, walnut, sesame, cocoa butter, unrefined palm).

Avoid refined, polyunsaturated-rich seed oils

Canola, safflower, sunflower, corn, soy, grapeseed, rice bran and cottonseed oil—which Shanahan calls “dark calories”—are rich in polyunsaturated fat and omega-6 fatty acids. When processed, she explains that they can become toxic, causing low-level inflammation, which can lead to health conditions, such as acne and food allergies. Unfortunately, Shanahan points out that 30 to 60 percent of the average person’s diet is comprised of them.

Watch carb consumption and nix sugar

Similar to vegetable oils, sugar is toxic, says Shanahan, and our bodies do not require a lot of carbohydrates. Yet, because they are so plentiful and cheap to produce, food manufacturers rely on them. She recommends matching your carbohydrate consumption to the type and amount of exercise you do, and limiting total consumption to 30 to 100 grams per day.

Go sprouted and fermented

The probiotic bacteria in naturally fermented foods, such as yogurt and kefir, vinegar, miso, tempeh, sauerkraut and kimchi, promote gut and immune system health. Meanwhile, in sprouted foods (such as Ezekiel bread), the “enzymes in the seeds have woken up and converted nutrients to more bioavailable forms,” meaning they can be absorbed by our bodies more easily, Shanahan explains.

Frequent the produce aisle

Vegetables in particular are some of the “best sources of antioxidants and vitamins,” Shanahan says.

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