Many of us don’t really pay attention to our bodies. We exist solely from our heads, ignoring the rest. It’s the way a lot of women are taught to survive and be successful. We believe the brain is in charge, controlling every aspect of our body, health, daily functions, relationships. But that is not true. The instruction is bidirectional. The brain is the ultimate output center for all efforts of the body. There is a relationship between the brain and the body that’s mutually dependent and mutually supporting. This fundamental interconnection is what I call brain-body. Understanding the brain-body connection holds the key to reversing many chronic symptoms that you may feel you simply have had to live with.

A healthy brain-body connection is when your brain and your body are fully in sync and congruent in their mission and goals. Healing conversations are occurring. That is, your gut is having a healing conversation with your brain, and your heart is telling your brain’s overactive stress-response system that it can calm down. In short, having a healthy brain-body connection means that you do not have high levels of inflammation causing brain-body breakdown. This inflammation commonly arises as a result of the stresses and environmental toxins of modern life.

For many women, the brain and body are no longer allies; rather, they are on the brink of separation, even divorce. We’re meant to have an enlivening, broad, and deep conversation between the brain and the body in order to feel and look our best.

In 2015, I had an epiphany about the brain-body. I learned it the hard way: I fainted, crashed, and smacked my head. I struck a cold tile floor, hitting the back of my head so hard that I had what looked like seizures due to the trauma. The recovery process was slow and terrifying. For a few months, I lay in a dark room most of the time, nauseated, unable to work, unable to exercise, unable to walk. I was forced to be still for the first time in my life. I was forced to start with the gut-brain connection, which is arguably the most important area of medicine and science today. In many ways, we’ve been barking up the wrong tree in medicine for the past thirty to fifty years when it comes to mental and physical health. We must look at the way our gut talks to our brain and vice versa, and particularly at the gut microbes and their DNA, collectively known as the microbiome.

I had no choice but to learn the rules of the brain-body. Fortunately, you don’t have to hit your head to discover and apply those rules so that you can prevent or reverse anxiety, brain fog, a rising body-weight set point, burnout, depression, and those niggly memory issues that start to show up after age forty.

There are some symptoms that reflect a malfunctioning brain-body connection. These are sacred messages. The specific symptoms of a brain-body failure state may present differently depending on the person. For me, they arose at age fifty-two and included high cortisol levels, high blood sugar, food addiction, and a feeling that I couldn’t handle One. More. Thing. Common symptoms of an imbalanced brain-body connection include:

• Feeling overobligated and stressed, as if you are churning and not making progress

• Weight gain or difficulty losing weight

• Fluid retention, feeling puffy all over, dull skin color, sensitivity to chemicals

• Brain fog, sluggishness, trouble concentrating or thinking clearly, forgetfulness, or feeling like your short-term memory is slipping

• Leaky gut, which may appear as gas, abdominal bloating and discomfort, acid reflux, constipation, loose stool

• Feeling overwhelmed, restless, or anxious or feeling burned-out, exhausted, or depressed

• Difficulty sleeping through the night

• Cravings for sugar, alcohol, or dairy that you can’t ditch

• Resting bitch face

Many of us don’t realize that while the brain represents only 2 to 3 percent of the body’s total weight, it consumes 25 percent of the body’s glucose supply and 20 percent of the oxygen and cardiac output in the body. The brain is the biggest consumer of what we put into our bodies, and most of us don’t consider our brains when making food choices. Rather, we often think of how many calories certain foods contain and whether they will make us gain or lose weight. We rarely think of how our brain is going to benefit or suffer from our food choices.

The food you consume has the potential to help or hurt your gut first, then your brain, and finally the rest of your body. Food is information not only for the DNA of your cells but also for the DNA of the microbes in your gut, known as your microbiome (think of it as your second genome). The food on your fork determines your gene expression, hormone levels, immune activity—even the stress levels in your gut, your brain, and the rest of your body. Furthermore, a change in the food you eat alters the activity of the gut microbiota rapidly—within one to four days, and in some genes, within six hours. That’s fast.

Foods contaminated with glyphosate—i.e., conventional wine and genetically modified foods, like corn chips—can contribute to a sudden imbalance. Other food groups that can cause an imbalance are gluten and casein—the most common protein in dairy—which can trigger the immune system.

When your gut microbiota changes, so does your brain. That’s why nutrients matter. In addition to the food we eat, some other potential causes of brain-body dysfunction include:

• Environmental toxins: We’re commonly exposed to environmental toxins that harm our brains. These include exposure to everyday chemicals found in our clothing, food, and furniture. Environmental toxins cause inflammation, which lead to too much or too little pruning of synapses and can increase oxidative stress. Lead converts weak and mild stress hormones into stronger stress hormones, which then tax the brain and the body. Nausea and balance issues (which can indicate inflammation) can arise from consumption of cadmium and/or arsenic. You may experience increased fight-or-flight symptoms, difficulty recovering from stressful events, a compromised digestive system, difficulty learning new tasks or skills, memory issues, and declining executive function.

• Hypothalamus-pituitary-adrenal axis, or HPA dysfunction: The HPA axis regulates your mood, sex drive, immunity, digestion, energy, metabolism, and stress response (fight-flight-freeze). It’s in charge of whether our nice or mean sides come out. There are many ways to mess up the HPA. More stress than you can handle, poor sleep or sleep deprivation, and inflammation are the main culprits. Chronic stress can keep your HPA in a jacked-up, overactivated state that is hard to regulate. If unaddressed, you may develop an underactivated, underresponsive HPA. Both are brain-body failure states. Symptoms of a dysfunctional HPA are increasing weight, brain fog, and anxiety.

• Injury or altered blood flow: Problems with blood flow to the brain can accumulate over time or with a sudden trauma. Head traumas from accidents or sports injuries are the ones we often hear about. But what are less discussed are the small accumulated injuries that result from issues within the body, such as excess carbohydrate intake and resulting blood sugar problems or high blood pressure, which can cause damage to the brain’s blood vessels, inflammation, and weight gain. Decreased cerebral blood flow may cause brain fog, memory loss, fatigue, anxiety, depression, low libido, hormone imbalance, and neurodegenerative disease.

Men and women differ dramatically in the brain-body connection. We know there are distinct structural and functional differences between the female and male brains. For example, women tend to have a larger hypothalamus—the seat of memory, learning, and emotional regulation. Men tend to have a bigger amygdala—the center of fear. Not only are there structural differences; there are functional differences, too. Brain-body conditions like anxiety, depression, and insomnia are twice as common in women as they are in men. We believe this is due to differences in brain chemistry, hormones, and cultural gender norms, such as the tendency for women to care for children and the elderly.

Menstrual cycles and the hormones that govern them make women more sensitive to stress signals and restricted energy intake (i.e., calorie restriction). Women respond differently to changes in dopamine activity, the brain chemical responsible for pleasure, satisfaction, and reward. This may help explain why women are more likely to experience food addiction. And women have a biological imperative to “tend and befriend,” meaning that under stress, we perform better when we connect with like-minded people (our herd) and leverage oxytocin, the hormone of love and connection.

Estrogen is the fundamental regulator of the female brain-body. In the brain, estrogen polices key biological functions like glucose transport, metabolism, and mitochondrial function—the way you produce energy. In the body, estrogen protects you from weight gain, ravenous appetite, insulin resistance, diabetes, and cancer. In sum, estrogen has hundreds of jobs beyond the usual female tasks that come to mind, like growing breasts and hips. And starting around thirty-five to forty, estrogen levels may decline, leaving women feeling unmoored.

When estrogen levels start to decline in perimenopause, a sequence of events unfolds that may put a woman at increased risk for insomnia, anxiety, depression, having a stroke, and developing dementia and Alzheimer’s disease. What’s unique to women is this sudden loss of estrogen and how it makes the brain-body’s metabolism stall and then dramatically decline, putting women at risk of future disease.

A women’s metabolism is further compromised by the change in crosstalk between estrogen and other chemical messengers in the body, like leptin (the hormone that tells you to put down the fork), ghrelin (the hormone that tells you to pick up the fork), adiponectin (the hormone that tells your body to burn fat), and sex-hormone-binding globulin (the sponge that soaks up free levels of other sex hormones, including estrogen). Some women compensate well for the loss of estrogen that begins in their forties; most do not. If you’re over forty and have been unhappy with how your body is changing, you may have brain-body dysfunction.

Often symptoms, like brain fog, get dismissed by doctors as part of the aging process. But these symptoms are not normal—they are signs of a brain-body that is out of sync and needs attention, as it could be the first step on the road to dementia or Alzheimer’s. It is essential for both doctors and women alike to be aware of the physiological differences between the male brain and female brain.

It is vitally important to connect the dots between the hormonal transitions that women experience and the impact these transitions have on the female brain. “Brain” symptoms such as brain fog, anxiety, or memory loss can be related to the different stages women go through in their life (pregnancy, perimenopause, and menopause), making them vulnerable to certain health issues.

I have been asked whether Brain Body Diet is a “diet” book. I use the term “diet” in the ancient Greek sense of the word: a prescribed way of living, of regular, daily work, not simply a restricted eating regimen that’s a short-term means to an end.

My protocols aim to boost neurogenesis in women—and lots of it. Neurogenesis is the ongoing growth and development of new nerve cells (neurons), which contribute to functions like learning, emotional regulation, and memory. Think of neurogenesis as a sports coach who is constantly developing his or her athletes and growing the team with new recruits. So it is with your brain. As your brain continues to grow and develop, the coach keeps recruiting new support cells while taking care of the regular cells. The coach keeps an ongoing supply of precursor cells at the ready, and once they enter the matrix of the brain as new nerve cells, the coach improves the connections between them (synaptogenesis). Go, team.

Neurogenesis occurs throughout life, even in adulthood, but it can slow down, leading to declining brain function and cognition, like a team that sat on their butts over the holidays. The protocols in Brain Body Diet help you compensate for reduced neurogenesis with the right detoxifying foods, targeted exercises, and stress-relieving activities so that you can reinstate neurogenesis and keep it going as you age. Together these lifestyle factors create more brain resilience.

I spent more than three years researching the science behind Brain Body Diet to create comprehensive, precise, and personalized lifestyle medicine protocols that feed our brain-body with the most-proven nutrient-dense foods, psychobiotics, behaviorceuticals, and nutraceuticals.

A key step in all of the protocols is intermittent fasting. Intermittent fasting (IF) is when you restrict eating to a specific window of time after an overnight fast. I fast seven days a week for sixteen hours per night. I will have my last meal at 7 p.m. and wait until 11 a.m. the following day to eat my first meal. If you are new to it, I recommend beginning with a twelve-hour window, only a few nights a week. The potential benefits of IF include weight loss, assisting your body in removing toxic substances, preventing inflammation, and decelerating disease, helping you reset key metabolic and stress pathways, and ultimately, aging more slowly. This process gives your body more time to rebuild healthy cells. IF has also been shown to reduce neurodegeneration. By giving the body a break from constant fueling and digestion, we create a window to focus on structural needs and to heal.

I want to create a sense of greater connectedness with my protocols and nurture neurospirituality. You can use your connection to something greater, no matter what it is, to improve your brain-body connection. In other words, you can use your beliefs along with the basics of neuroscience to improve spiritual neuroplasticity and build a better, healthier brain-body connection. Something as simple as a walking meditation or prayer on a daily basis can lead to important changes. I recommend Kundalini yoga, but find a practice that suits you and stick with it. A daily practice can increase blood flow to the brain, grow the grey matter, reduce the focus on self-centeredness, and create a connection to something greater. This has measurable effects on the brain that improve brain-body physiology and provide a shield against the normal stress of daily life.

As a physician guiding women through lasting health transformations, I’ve found that forty days is the most effective amount of time to notice the way you use your brain and then more effectively restore your brain-body connection. It is exactly how long it took for me to repair my brain-body, and it is an ancient container for transformation in the yoga and particularly the Kundalini tradition. You need the full forty days to detox your brain and reverse the symptoms you are experiencing in the body.

Environmental toxins are substances that work in direct opposition to natural healing. They can either create a negative and potentially life-altering pattern or worsen a negative pattern in the brain-body. They tell your brain to stop healing the body, and they can make you jittery and reactive. We carry them in our fat tissues and release them with fat loss. Most of us carry the most common environmental toxins in our bones, and every day—through our diet, the water we drink, the products we use—we take in a little more lead, mercury, cadmium, and arsenic. Then, at age thirty-five, as your bone buildup slows down and bone breakdown begins, you slowly release these substances into your bloodstream. From this internal storehouse of toxic substances, as well as new exposures, our brain-bodies can become a little more poisoned each day with the food we eat (especially foods with pesticides, herbicides, genetically engineered ingredients, hormones) or mold in the water we drink, the products we use, and the air we breathe.

This trash begins to pile up in the brain, and the brain-body becomes desperate for someone to take out the trash and allow it to heal. We do that by strengthening our DNA-repairing genes and habits, and by improving our stress-coping habits and how we cope with environmental toxins.

It is no longer a luxury to detoxify; it’s a requirement of healthy living. This is such an important topic that I devote a whole chapter to discussing it, and I provide clear steps on how to detoxify using food as your shield. In addition to intermittent fasting, I teach women about foods that are rich in antioxidants, foods that help the liver with detoxification, foods and teas that help make more glutathione (when you’re low in glutathione, environmental toxins linger in your system, potentially damaging your cells), as well as brain botanicals that help protect you against toxicity.

One of the most surprising truths I learned in writing this book was how full of environmental toxins I was, totally unbeknownst to me. I ate organic exclusively except when at certain restaurants. I detoxed a few times per years. I had a little mercury built up, but I was taking care of it. I thought I was doing everything right. Not so.

I found I was in the toxic range for glyphosate¹ , the broad-spectrum antibiotic and herbicide used to kill weeds. I was shocked to discover we have a weapon of mass destruction in our food supply that is ruining the gut-brain connection. It disrupts the integrity of the gut barrier and may then disrupt the integrity of the blood-brain barrier, leading to inflammation. It’s associated with increased anxiety, attention deficit, depression, weight gain, cancer, memory, and other brain-body problems. Its residues are commonly found in GMO foods and conventional wine.

I also encourage women to stimulate their lymphatic system, which can be likened to the waste-clearance system for your whole body. To keep your lymphatic system functioning properly and doing its job to dispose of waste, it’s important to increase your water intake, keep your weight at a healthy set point, get more sleep, sit less, and exercise more to keep your circulation moving. One of the best ways to improve your lymphatic circulation and aid in the removal of toxic substances is with resistance exercise. Even if it’s just ten to fifteen minutes of brief muscle contractions, it can increase the lymph flow by 300 to 600 percent.

Brain fog can arise from a number of root causes. The gut and mitochondria are the first places I look for the low-level inflammation that can contribute to bodily symptoms such as stiffness, puffiness, and neuroinflammation, an inflamed brain. A leaky gut contributes to inflammation in the body, which causes brain inflammation, making your brain foggy. Other food intolerances—such as to dairy, grain, sugar, or nightshade vegetables—may be causing a problem for you in your gut. Environmental toxins, the wrong foods, and lifestyle choices can make you inflamed. Sitting too much and sleeping too little can rob you of the mental clarity that you deserve. The symptoms you experience from inflammation are what I term the “fallout of a maxed-out modern life.”

I believe disease begins in the gut, and anxiety is no exception. It must be healed in the gut first. In Brain Body Diet, I teach you how to immerse yourself in a prescribed way of living that will put your brain and body back into a peaceful alignment, free of the suffering that results from anxious thoughts and feelings, no longer clinging to things beyond your control and creating an unnecessary orgy of stress. That’s the lifestyle medicine of the Brain Body Diet—to create a balanced state of body, mind, and spirit—starting first with simple additions of food and lifestyle tools to your daily regimen.

Emerging data suggest that communication between the gut and the brain plays a key role in the development of anxiety, depression, and cognition—meaning that you need healthy and diverse microbiota in order to develop healthy and diverse feelings, thoughts, and habits.

If you suffer from anxiety, it is important to be aware of hormonal imbalances that can cause symptoms of anxiety. Sex hormones and neurotransmitters in the brain interact, which can contribute to imbalances. I advise women to find a doctor who will search for the root cause of their anxiety before prescribing medication. Some hormonal imbalances that can cause anxiety are:

• Dysregulated cortisol—high or low or both within the same day

• Insulin resistance—high insulin and high blood pressure

• Thyroid dysfunction—usually high, but low thyroid function can also mimic anxiety symptoms

• Low estrogen or low progesterone

While researching Brain Body Diet, I realized I may have never recovered my full brain function post-pregnancy—and my last pregnancy was well over a decade ago.

The hormonal cycles of puberty, pregnancy, and menopause can change a woman’s brain. Let’s backtrack a moment to neurogenesis. Neurogenesis is a good thing—you want to maintain growth, density, and plasticity of new nerve cells as you age, which means you need to keep building new connections between the new cells to improve blood flow to the brain. One crucial component of ongoing healthy synaptogenesis is the “pruning shears,” which come out to trim the inappropriate neural connections (the ones that are no longer useful) and make more room for the appropriate ones. This is why you don’t remember every single calculus equation learned in school: Your brain needed to make room for your work projects, your kids’ activities, your social agenda—whatever information you need on a daily basis. The most aggressive and healthy pruning occurs in adolescence (probably to help with learning) and again in pregnancy and postpartum (most likely to promote bonding with your baby).

The goal is to have more growth than pruning; it’s better for your memory and learning. After a certain age, too much pruning may cause memory issues, Alzheimer’s disease, and schizophrenia. Unfortunately, neurogenesis and synaptogenesis are vulnerable to brain “insults,” including poor diet, chronic stress, disrupted sleep, inflammation, and environmental toxins.

A woman’s hormones fluctuate regularly and predictably throughout the menstrual cycle. For instance, the highest testosterone levels occur on day nine, the highest estradiol levels on day twelve, and highest progesterone levels on day twenty-one or twenty-two. These fluctuations all have impacts on the brain. Testosterone increases libido, estrogen decreases neuroinflammation and increases the growth of new brain cells, and progesterone has a calming effect.

Among the hundreds of patients I have had complete my protocol, I’ve found that when you repair the brain-body, beginning first with restoring integrity to the gut-brain axis, you can expect to feel mentally sharp and focused and have an easier time recalling that word on the tip of your tongue.

You can expect to no longer struggle with puffy inflammation and a rising body-weight set point. You can get your hormones back on your side, which will help you sleep well at night and reestablish a normal appetite. You’ll no longer feel like you’re rushing from task to task. You will feel resilient and adaptable.