Book Review: “6 Keys: Unlock Your Genetic Potential for Ageless Strength, Health and Beauty,” by Jillian Michaels


Jillian Michaels may be the most popular fitness expert on the planet. She has over 100 million followers across her media empire, which includes hit TV shows like “The Biggest Loser;” nine fitness books; numerous best-selling exercise DVDs; and Apple and Google’s number-one-rated fitness app.

Does she have more to say; should you read this book?

Yes! Jillian’s newest book has some fresh ideas in it and generally excellent advice on health and wellness. This book differs from her prior contributions, which mostly focused on weight loss. This book focuses on aging well. Jillian is only 44, but you’re never too young to follow the recommendations in this book to live not just a long life, but a healthy, vital one as well.

Summary of the 6 Keys

The “6 Keys” of the title are the six ways to age well. They are science-based, and Jillian says that her book is the first that pulls them all together in one place. They are:

  1. Mastering Macromolecules—this refers to how your body uses proteins, carbohydrates, lipids (fats) and nucleic acid (found in RNA and DNA). Some theories of aging blame free radical damage to these macromolecules for accelerating our demise. To inhibit this damage, you should consider calorie restriction. And when you do eat, avoid unhealthy fats, sugar and processed foods; eat as many whole vegetables and fruits as you can; and exercise, ideally via HIIT (High-Intensity Interval Training). This is always good advice, whatever theory it falls under.
  2. Engineering Epigenetics—this is about how genes are not necessarily destiny; you can turn the expression of genes on and off with lifestyle changes. Do this through, once again, calorie restriction. And, when you eat, ensure a moderate intake of healthy fats; drink green tea; eat cruciferous vegetables; get plenty of B vitamins; spice your food with turmeric; exercise; don’t smoke; and limit sun and pollution exposure.
  3. Strong-arming Stress—stress spikes adrenaline and cortisol, which ages you. Stress can harm your digestion, affect your vision and hearing, and increase your risk of hypertension and stroke. It negatively affects your sleep, memory and immune system. It can harm your DNA and make you fat. Help address it by doing everything in #1 and #2.
  4. Owning Inflammation—chronic inflammation ages you and can lead to obesity and disease. It can even inhibit muscle, bone and brain cell creation. Tamp it down by doing everything in #1 and #2; eating fermented foods and foods high in lutein; taking omega-3, vitamins C and E, alpha lipoic acid, quercetin, and spirulina supplements; getting enough sleep (but not too much); and by shedding excess body fat, which secretes pro-inflammatory cytokines.
  5. Managing Metabolism—a fast metabolism is good for weight management, but a slow metabolism is associated with longer life. To slow aging, the goal is to get nutrient-detectors AMPK and sirtuins up while bringing IIS and mTOR down. Exactly what these are and why this is true is too involved to explain here. But calorie restriction; resveratrol, and glucosamine supplements; getting enough sleep and exercise; and a low sugar, non-keto diet may help.
  6. Tackling Telomeres—telomeres cap the ends of chromosomes.They shorten as cells divide, and longer telomeres are associated with longer life. Studies show that telomeres can be lengthened by doing all the things in #1-5 above. Also, these nutrients are thought to help: magnesium, vitamins D, B6, B12, alpha lipoic aid, beta carotene, and omega-3 fatty acids. De-stressing is important, too.

A Fresh Take on Exercise

Jillian recommends an exercise approach she calls Metabolic Circuit Training, or MCT, four days a week. MCT combines resistance training and circuit training to stimulate higher calorie burning. Two days a week, you do HIIT workouts. And Sunday is a mandatory rest and recovery day.

The recommendations are based on solid rationale, and detailed instructions for when and how to exercise different body parts during the week are provided. Workouts can also be streamed from her app (accessing the full features requires a subscription).

Other Cool Stuff I Learned From This Book

Often when I read wellness books I find that I’ve heard it all before, even if it’s packaged up differently. But I learned some new things from Jillian. Here are a few:

  • I had heard that strenuous exercise can cause oxidative stress, and that therefore moderate-intensity research is best. Jillian cites research showing that the body compensates for this by making higher levels of antioxidants. However, consistent levels of exercise intensity are key; your body needs to become accustomed to the intensity to balance the stress. Be consistent!
  • Organic cold brew coffee is healthiest. She doesn’t get into why, but I did my research and found that there are a lot of reasons to choose organic-paper-filtered, organic cold brew. She also cites evidence that two strong cups a day is the ideal amount for getting the health benefits of coffee before the drawbacks kick in from more cups.
  • Being stressed in the evening can make you fat. Stress increases levels glucocorticoid levels, which don’t increase your fat cells in the daytime, but do in the evening. Who knew? Aids to de-stressing include eating well and exercising at a moderate intensity level. Also incorporate meditation, yoga, Tai Chi or other “mind-body interventions” into your day.
  • Alcohol inhibits fat metabolism and sends estrogen levels soaring. Yet in moderation, alcohol has health benefits, Jillian says (my opinion on this is below). The middle road is your best bet with alcohol, caffeine, supplements, and many other lifestyle choices.

A Few Quibbles

Overall, this book provides excellent health advice consistent with the latest scientific studies. It’s written in a casual, girlfriendly tone that makes scientific findings easy to understand. I quibble with a few of her recommendations which seem based more on personal opinion than research. For example, Jillian says to avoid soy without offering a rationale. The latest science on soy is that it inhibits bad estrogen and supports good estrogen, and is therefore recommended for men and women alike (as long as it isn’t highly processed).

Jillian also finds that moderate drinking of alcohol can be good for you. I wish this one were true! But the latest expert advice is that no amount of alcohol is beneficial, and I am surprised she has such a tolerant position on it in an anti-aging book. She also finds that meat (albeit organic, pasture-raised) can be part of a healthy diet. Yet the latest studies show that all animal foods can cause inflammation, and one of her 6 Keys is all about avoiding inflammation.

Granted, Jillian advises against drinking a lot of alcohol and eating a lot of red meat. But her shunning of healthy foods like soy, and openness to other foods that go against the 6 keys, made me feel that research for the book, while extensive, wasn’t as rigorous as it could have been.

Another quibble—Jillian recommends using protein powder with branched-chain amino acids (BCCA’s), without mentioning that it can cause acne in some people. In addition, experts are now saying that most people, including vegetarians, get enough protein from food. Excess protein can stress kidneys and lead to kidney stones.

Overall, a Thumb’s Up

In spite of these points, there is much more right than wrong with this book, and you are likely to learn some new things that help you be healthier and live longer. I plan to buy her app and start adopting her exercise recommendations immediately. Thank you, Jillian, for continuing to motivate and teach us!

Here’s my review of “The Future of Nutrition,” by T. Colin Campbell.

Read about “Breathe: The New Science of a Lost Art,” by James Nestor.

Read my review here of “Your Body in Balance: The New Science of Food, Hormones and Health,” by Neal D. Barnard, MD FACC.

Vicki Spellman

Vicki Spellman is a certified Holistic Nutritionist (AFPA) and Senior VP at a large healthcare communications firm.

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