David Perlmutter, MD

We call this complex internal ecology that thrives within us and its genetic fingerprint the microbiome (micro for ‘small’ or ‘microscopic,’ biome referring to a naturally occurring community of flora occupying a large habitat—in this case, the human body).

“The Greek physician and father of modern medicine, Hippocrates, first said in the third century B.C.E., ‘All disease begins in the gut.’”

If you were to ask someone on the street about depression, you’d be likely to hear something along the lines of ‘It’s a chemical imbalance in the brain.’ Well, I’m here to tell you that that would be incorrect. Two decades of scientific literature highlight the role of inflammation in mental illness, from depression to schizophrenia.

We really have to pay attention to how our gutsy tribes are fed and nurtured. We also have to ensure the integrity of the gut lining.

But what if being overweight or obese has less to do with willpower or even genetic forces and more to do with the microbial profile in the gut? What if we owe our obesity challenges to a sick and dysfunctional congregation of intestinal bugs?

I can’t reiterate this enough: The health and variety of your belly’s bugs directly depend on the foods that you eat.

Make no mistake: blood sugar regulation is priority #1 when it comes to preserving brain function and resisting Alzheimer’s disease.

The fatter you are, the smaller your brain.

If you’re a chronic headache sufferer, why not try a gluten-free diet? What have you got to lose?

We need to change our attitudes about cholesterol and even LDL; they are our friends, not our foes.

Remember, if you do nothing else recommended in this book but eliminate gluten and refined carbohydrates, you will experience profound positive effects.

The information that I will reveal to you is not just breathtaking; it’s undeniably conclusive. You’ll be shifting how you eat immediately.

Beyond calories, fat, protein, and micronutrients, we now understand that food is a powerful epigenetic modulator—meaning it can change our DNA for better or worse.

It is my belief that gluten is a modern poison.

Gluten—which is Latin for ‘glue’—is a protein composite that acts as an adhesive material, holding flour together to make bread products, including crackers, baked goods, and pizza dough.

The bottom line is that if you want to reduce oxidative stress and the action of free radicals harming your brain, you have to reduce the glycation of proteins. Which is to say, you have to diminish the availability of sugar. Pure and simple.

Carbohydrates—not dietary fats—are the primary cause of weight gain. (Think about it: Many farmers fatten animals destined for the butcher block with carbohydrates like corn and grain, not fats and proteins.

For many, health may not be the most important thing in life, but without it, nothing else matters. And when you have good health, pretty much anything is possible.

Be strict about going to bed and getting up at the same time every day, 365 days a year. Don’t shift your sleep habits on weekends or holidays or vacations.

Keep in mind, though, that an hour daily spent working out hard won’t erase the effects of sitting down for the rest of the day.

Low-carb does not mean high-protein. The Grain Brain Whole Life Plan calls for a limited daily intake of protein—no more than about 46 grams for women and 56 grams for men.

Strive for progress, not perfection.

No doubt there is a time and place for medications, be they over-the-counter or prescribed. But we live in a world where we are too quick to medicate, self-prescribe, and depend on pills.