“Though you can boil, extract, and refine living tissue to isolate the protein, carb, or fat, you do so only at the cost of everything else that held the cells and organs together.”
Dr. Catherine Shanahan’s Deep Nutrition: Why Your Genes Need Traditional Food is a detailed yet comprehensible overview of the ways in which the American diet is slowly killing us. By providing thorough scientific explanation,1 Dr. Shanahan and her husband Luke elucidate just how unhealthy the standard American diet is for us on a cellular level, and how it ultimately causes or encourages many of modern society’s health problems—joint problems, eczema, erectile dysfunction, infertility, tooth misalignment, various cancers, birth defects, heart problems, etc.
Before I read Deep Nutrition, I only thought of my diet in terms of how it affected my health, but the impact of my food choices goes much deeper than that, and the generational effects of diet are laid out thoroughly. Through a survey of epigenetics—the study of how certain existing genes can be activated or deactivated by lifestyle choices (like exercise, sleep, and dietary habits)—Dr. Shanahan focuses on how flourishing genes inherently lead to beautiful, healthy people. She cites studies of ancient cultures and their diets, and critiques financially-incentivized studies that have sloppy science and promote unhealthy and unnatural foods. The historical studies get a bit carried away with trying to scientifically examine beauty (such as Marquardt’s Mask, a phi-based description of archetypal or ideal forms of beauty), but they never get too far away from the main concerns of diet and health. While some of the more scientifically dense sections were difficult to wade through, they give credence to the intuitive suggestions that Shanahan makes regarding traditional foods.
In effect, DNA seems capable of collecting information—through the language of food—about changing conditions in the outside world, enacting alteration based on that information, and documenting both the collected data and its response for the benefit of subsequent generations.
Years of study and experimentation in the authors’ personal lives serve to provide the book with a robust foundation; but the book’s careful structure is also very effective in convincing the reader of the viability of the Human Diet. Due to this, a summary is necessarily going to inadequately represent the argument. So, I won’t try too hard to convince anyone of the argument’s validity; you should just read the book—for your sake and the sake of your children, grandchildren, and so on. My contribution will be to adopt a healthier lifestyle and convince others that the dietary guidelines suggested here are superior by living having a healthier body.
The American diet is based around cheap, convenient, toxic foods (because nutritionally lacking foods are cheaper to produce). Shanahan’s suggested Human Diet, while nutritionally robust, is also more expensive and time-consuming to prepare, and you also may be required to force down some foods that you currently have no taste for.2 But, the author predicts that after some initial sacrifice, the health benefits begin to outweigh the drawbacks; and the author does not suggest a cold-turkey changeover, but rather a gradual transition.
The two main culprits that are severely affecting are health are sugar and vegetable oils. Huge portions of the book are dedicated to convincing the reader just how harmful these two substances are to our bodies. They are both ubiquitous—salad dressing, bread, crackers, peanut butter, granola, french fries… and restaurants almost all use (and reuse) low quality oils with harmful effects that are only increased when they are heated. Add this to the dearth of nutrients in grain fed meats, and produce that is picked before it is ripe and shipped across the country or canned or what have you, and it is clear that the health-conscious individual is fighting an uphill battle.
It is especially concerning—given the gratuitous amounts of sugar that we consume without thinking about it—that seemingly healthy or at least benign foods like pasta, rice, and potatoes are essentially sugar once our bodies process them.
The four pillars of Dr. Shanahan’s human diet are:
–Meat (preferably not grain fed) cooked on the bone
–Organs and other nasty bits3
–Fresh, preferably raw or lightly cooked plant and animal products
–Fermented (or sprouted) foods
The book also covers the importance of exercise in addition to careful food selection; it discusses the ways in which the two work in conjunction regarding your health. Exercise cleans the blood stream, it releases endorphins which help with depression; it does not just burn calories, but generates signals which encourage muscle, bone, and tendon growth instead of fat growth; it improves memory as we age; it reduces stress and builds more blood vessels.
Toward the end of the book, practical implementation is considered, and in the second edition of the book a series of FAQs are answered. Deep Nutrition really opened my eyes to a number of things that I always intuitively thought seemed correct to me, and its comprehensive nature gives me confidence in implementing its espoused eating principles into my own life. I also commend it for its long-term view of things, as it led me into a zoomed out view of my potential impact on my descendants—it has given rise to a greater focus on taking care of myself physically and mentally.
If you just want the dietary guidelines, Dr. Shanahan has also written Food Rules: A Doctor’s Guide to Healthy Eating, which is much more practically oriented, non-scientific, and does not include as much of a historical basis for its arguments. Dr. Shanahan’s site is also a great resource for implementing the Human Diet—including helpful items such as this list that differentiates between healthy and harmful fats.
Things aren’t as cut and dry as Dr. Shanahan makes them seem, but the elevator pitch of “stop eating vegetable oils and sugars” is a good start.
1. I am less than a novice in the field, and mostly reading this for the take-home message, so most of the jargon-dense biological and nutritional information was such that I could only barely grasp it when it was being presented but could not adequately regurgitate it now.
2. Livers, skin, eyeballs, bone marrow, sauerkraut, etc. (but there are suggested substitutes).
3. One of the most eye-opening portions of the book was an analysis which explains how eating a specific part of an animal is generally beneficial to that part of you, e.g. eating eyes is good for your eyes; drinking bone broth is good for your bones; skin for skin.