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Switch on Your Brain: The Key to Peak Happiness, Thinking, and Health

Switch on Your Brain: The Key to Peak Happiness, Thinking, and Health

by Caroline Leaf
Jill Eileen Smith

Learn More | Meet Caroline Leaf | Meet Jill Eileen Smith

It was only a few decades ago that scientists—including those who trained me—considered the brain to be a fixed and hardwired machine. This view saw the damaged brain as incurable. They believed brain damage was hopeless and untreatable, whether the effects were from stroke, cardiovascular event, traumatic brain injury, learning disabilities, traumas, PTSD, OCD, depression, anxiety—even aging.

All of these causes and conditions were seen as largely irreversible. Because this was the presiding view of the brain, I was trained back in the ’80s to teach my patients compensation, not restoration of function. I was trained in the conventional wisdom of the time that said brain normality was an impossibility for those with mental limitations or brain damage of any kind. Being a student of the Bible, however, I was deeply familiar with and constantly comforted by Romans 12:2: “Do not conform to the pattern of this world, but be transformed by the renewing of your mind” (NIV). I knew this famous and fabulous “renewing of the mind” passage was a truth I needed to apply to my patients’ care to help them overcome their deficits. So my relentless search of this truth as a scientist began.

I was struck by how my patients, using the therapeutic techniques I was developing from my research, belied the negative picture conventional science presented of the human brain at that time. These results confirmed that the brain, far from being fixed in toxicity, can change even in the most challenging neurological situations.

I was in awe of what each patient displayed in terms of what you can do when you set your mind to it. Each new scientific study in this direction confirmed what I knew intuitively to be true: We are not victims of our biology or circumstances. How we react to the events and circumstances of life can have an enormous impact on our mental and even physical health.

As we think, we change the physical nature of our brain. As we consciously direct our thinking, we can wire out toxic patterns of thinking and replace them with healthy thoughts. New thought networks grow. We increase our intelligence and bring healing to our brains, minds, and physical bodies. It all starts in the realm of the mind, with our ability to think and choose—the most powerful thing in the universe after God, and indeed, fashioned after God.

It is with our phenomenal minds that we understand the truths set down in our spirits. It is with our minds that we wire these truths into the brain, which is part of the body. It is with our minds that we choose to develop the spiritual part of who we are and “Therefore put away all filthiness and rampant wickedness and receive with meekness the implanted word, which is able to save your souls” (James 1:21 ESV). It is with our minds that we reject or believe the lies of the Enemy, the Prince of Lies. It is with our minds that we change the physical reality of the brain to reflect our choices. It is with our minds that we decide to follow God’s rules and live in peace despite what is going on around us. It is with our minds that we choose to follow the lies of Satan and spiral into mental, physical, and spiritual disarray.

Thought changes the structure of matter. God said, “Let there be light” (Gen. 1:3), and his words produced the physical earth. And science, which, again, is just catching up with the Word of God, is confirming this reality in a tangible and thought-provoking way with eminently clear accounts arising from the burgeoning field of neuroplasticity research.

Neuroplasticity by definition means the brain is malleable and adaptable, changing moment by moment of every day. Scientists are finally beginning to see the brain as having renewable characteristics (as in Rom. 12:2); it is no longer viewed as a machine that is hardwired early in life, unable to adapt, and wearing out with age. With example after fascinating example, exceptional scientists talk about and demonstrate— using brain-imaging techniques and the evidence of behavioral changes—how people can change their brains with their minds. We can see and measure the activity of the mind through the firing of neurons. We can even predict the seeming elusiveness of the main functions of the mind—that of thinking and choosing—through quantum mechanics.

I continue to find myself moving in a world of engrossing truths, and my spirit leaps inside of me. The fact that the brain is plastic and can actually be changed by the mind gives tangible hope to everyone, no matter what the circumstance.

  • autistic children cope in academic and social environments
  • senior citizens sharpen their memories to the point that in their eighties they change careers and obtain degrees
  • young men and women who grew up in abject poverty and a lifestyle of selling and taking drugs do a complete about-face in their lives, go back to school, and become leaders in their communities
  • car accident victims who had been written off by neurologists as “vegetables” retrain their brains to the point that they complete their schooling up to a tertiary level and go on to become successful, contributing citizens
  • students labeled as learning disabled with years of therapy and no hope left master learning and achieve grades they and their parents only dreamed of
  • schools in some of the worst third-world areas in Africa, in which students could not pass to the next level, become schools on the minister of education’s “most improved” list
  • children with dyslexia learn to read and write and even help their parents study for exams successfully
  • suicidal and emotionally traumatized minds set free
  • entire schools improve grades across core subjects

And the list goes on.

Science is hovering on a precipice as we recognize the responsibility and impact of our thinking and the resultant choices we make, which have ramifications right down to the ways in which the genes of our bodies express themselves. Deuteronomy 30:19 is becoming a reality in the world we live in today as we begin to see the effects of choice in the brain and body: “I set before you life and death, blessing ; choose life so that you and your descendants may live.”

How we think not only affects our own spirit, soul, and body but also people around us. Science and Scripture both show how the results of our decisions pass through the sperm and ova to the next four generations, profoundly affecting their choices and lifestyles. The science of epigenetics (the signals, including our thoughts, that affect the activity of our genes) explains how this plays out. This reminds me of the Scripture, “he punishes the children and their children for the sin of the parents to the third and fourth generation” (Exod. 34:7 NIV).

That the brain is plastic and can be changed moment-by moment by how we direct our thinking—in other words, the choices we make—is a top idea on the bestseller lists, and it actually is the key to switching on our brains. Add to this the fact that every morning when you wake up, new baby nerve cells have been born while you were sleeping that are there at your disposal to be used in tearing down toxic thoughts and rebuilding healthy thoughts. The birth of these new baby nerve cells is called neurogenesis, which brings to mind, “The Lord’s mercies . . . are new every morning” (Lam. 3:23).

What a remarkable and hopeful portrait of the endless adaptivity of the human brain God has given us.

This book is divided into two parts, with the overall goal of showing you how to switch on your brain. Part 1 uncovers the keys to doing so. In part 2 you will see how all these keys work together in my 5-Step Switch On Your Brain Learning Process during my 21-Day Brain Detox Plan. Here I will lead you through a process of switching on your brain to achieve peak happiness, thinking, and health.

Here are some of the key points in this book:

  • Your mind is the most powerful thing in the universe after God.
  • Free will and choice are real, spiritual, and scientific facts (Deut. 30:19).
  • Your mind (soul) has one foot in the door of the spirit and one foot in the door of the body; you can change your brain with your mind and essentially renew your mind (Rom. 12:2).
  • You can develop your spirit through choices you make in your mind to be led by the Holy Spirit (Gal. 2:20).
  • Your body is not in control of your mind—your mind is in control of your body, and your mind is stronger than your body. Mind certainly is over matter.
  • You are not a victim of your biology.
  • You cannot control the events and circumstances of life, but you can control your reaction to those events and circumstances (Matt. 7:13–14; Gal. 6:7–8).
  • When you think, you build thoughts, and these become physical substances in your brain. “As he thinks in his heart, so is he” (Prov. 23:7).
  • Good thinking = good choices = healthy thoughts; toxic thinking = toxic choices = toxic thoughts (Deut. 30:19).
  • You are designed to stand outside yourself and observe your own thinking and change it (Rom. 12:2; 2 Cor. 10:5; Phil. 3:13–14).
  • You are designed to recognize and choose the right things to think about (Josh. 24:15; Eccles. 7:29; Isa. 30:2).
  • Each morning when you wake up, you have new baby nerve cells born inside your brain to use wisely as you remove bad thoughts and wire in new ones (Lam. 3:23). This is called neurogenesis.
  • You have been designed for deep, intellectual thought (Ps. 139:14).
  • You are wired for love, and fear is a learned and not a natural response (2 Tim. 1:7).
  • You have the mind of Christ (1 Cor. 2:16).
  • You are made in God’s image (Gen. 1:27). All this knowledge will help you realize these truths:
  • Happiness comes from within and success follows—not the other way around.
  • You can learn how to learn and deepen your intellect.
  • You can overcome those learning issues.
  • You can get the chaos in your mind under control.
  • You don’t have to walk around in guilt and condemnation.
  • If you wired those toxic thoughts in, you can wire them out.
  • You don’t have to get stuck in bad habits; you can change them.
  • You can overcome feelings of rejection and hurt.
  • Forgiveness is not the battle you think it is.
  • You don’t have to worry about things that are out of your control.
  • You are not a victim of the things you shouldn’t be doing.
  • You don’t have to fear that if a condition runs in your family that you are going to get it (for example, Alzheimer’s, Parkinson’s, or depression).
  • You can balance your over-thinking and over-analyzing mind.
  • You can overcome and control depression and anxiety— some scientists are showing you can even control and overcome schizophrenia and OCD.
  • You don’t have to keep digging into the past to get free from it.
  • You can be happy and filled with peace regardless of your circumstances.

If you have nodded your head at even one of these, it is time for you to be set free in your mind to pursue all God has for you. Read on. It is time for you to Switch On Your Brain and find the keys to peak happiness, thinking, and health.

In part 1, I explain through science and Scripture how the concepts described above come together.

In part 2, you will find my 21-Day Brain Detox Plan, which incorporates my scientifically proven 5-Step Switch On Your Brain technique based on my research, my years in clinical practice, and doing seminars and conferences around the world. This section is practical and filled with key, proven strategies that will help you develop a lifestyle of renewing your mind and aligning it with God’s will so your divine sense of purpose can be released (Eccles. 3:11).

You are truly designed for peak happiness, thinking, and health.

The debate in science is between the mind being what the brain does versus the brain doing the bidding of the mind. The position you adopt will impact how you view free will and choice.

The Mind Is What the Brain Does

The first argument proposes that thoughts come from your brain as though your brain is generating all aspects of your mental experience. People who hold this view are called the materialists. They believe that it is the chemicals and neurons that create the mind and that the relationships between your thoughts and what you do can just be ignored.

So essentially, their perspective is that the brain creates what you are doing and what you are thinking. The mind is what the brain does, they believe, and the ramifications are significant. Take, for example, the treatment of depression. In this reductionist view depression is a chemical imbalance problem of a machinelike brain; therefore, the treatment is to add in the missing chemicals.

This view is biblically and scientifically incorrect.

The Brain Does the Bidding of the Mind

Let’s look at this from the other angle of the argument: The brain is what the mind does.

You are a thinking being. You think all day long, and at night as you sleep, you sort out your thinking. As you think, you choose, and as you choose, you cause genetic expression to happen in your brain. This means you make proteins, and these proteins form your thoughts. Thoughts are real, physical things that occupy mental real estate.

Eric R. Kandel, a Nobel Prize–winning neuropsychiatrist for his work on memory, shows how our thoughts, even our imaginations, get “under the skin” of our DNA and can turn certain genes on and certain genes off, changing the structure of the neurons in the brain. So as we think and imagine, we change the structure and function of our brains. Even Freud speculated back in the 1800s that thought leads to changes in the brain. In recent years, leading neuroscientists like Marion Diamond, Norman Doidge, Joe Dispenza, Jeffrey Schwartz, Henry Markram, Bruce Lipton, and Allan Jones, to name just a few, have shown how our thoughts have remarkable power to change the brain. Our brain is changing moment by moment as we are thinking. By our thinking and choosing, we are redesigning the landscape of our brain.

Our mind is designed to control the body, of which the brain is a part, not the other way around. Matter does not control us; we control matter through our thinking and choosing.

We cannot control the events and circumstances of life but we can control our reactions. In fact, we can control our reactions to anything, and in doing so, we change our brains.

It’s not easy; it is hard work, but it can be done through our thoughts and choices. This is what I focus on in the second half of the book with my 21-Day Brain Detox Plan.

For now, rest in the assurance that what God has empowered you to do with your mind is more powerful and effective than any medication, any threat, any sickness, or any neurological challenge. The Scripture is clear on this: You do not have a spirit of fear but of love, power, and a sound mind (2 Tim. 1:7). We are not bound by the physical; we control the physical. You just have to look at the many inspirational survival stories of those who have overcome impossible odds throughout history and in the current day to know this is truth.

Choices Are Real

You are free to make choices about how you focus your attention, and this affects how the chemicals and proteins and wiring of your brain change and function. Scientists are proving that the relationship between what you think and how you understand yourself—your beliefs, dreams, hopes, and thoughts—has a huge impact on how your brain works.

Research shows that 75 to 98 percent of mental, physical, and behavioral illness comes from one’s thought life.

This staggering and eye-opening statistic means only 2 to 25 percent of mental and physical illnesses come from the environment and genes.

Thinking Activates Genes

Every day scientists are discovering the precise pathways by which changes in human consciousness produce changes in our brain and bodies. Our consciousness—this phenomenal gift from God to be able to think—activates our genes and changes our brain. Science shows that our thoughts, with their embedded feelings, turn sets of genes on and off in complex relationships. We take facts, experiences, and the events of life, and assign meaning to them with our thinking.

We may have a fixed set of genes in our chromosomes, but which of those genes are active and how they are active has a great deal to do with how we think and process our experiences.

Our thoughts produce words and behaviors, which in turn stimulate more thinking and choices that build more thoughts in an endless cycle.

Our Brains Are Shaped by Our Reactions

We are constantly reacting to circumstances and events, and as this cycle goes on, our brains become shaped by the process in either a positive, good-quality-of-life direction or a negative, toxic, poor-quality-of-life direction. So it is the quality of our thinking and choices (consciousness) and our reactions that determine our “brain architecture”—the shape or design of the brain and resultant quality of the health of our minds and bodies.

Science and Scripture both show that we are wired for love and optimism5 and so when we react by thinking negatively and making negative choices, the quality of our thinking suffers, which means the quality of our brain architecture suffers. It is comforting—and challenging—to know that negative thinking is not the norm.

Thinking Changes Our DNA

Taking this to a deeper level, research shows that DNA actually changes shape according to our thoughts. As you think those negative thoughts about the future—the week ahead, what a person might say or do, even in the absence of the concrete stimulus—that toxic thinking will change your brain wiring in a negative direction and throw your mind and body into stress. According to Dr. Herbert Benson, MD, president of Harvard Medical School’s Mind-Body Institute, negative thinking leads to stress, which affects our body’s natural healing capacities.

Toxic thinking wears down the brain.

The Institute of HeartMath, an internationally recognized, nonprofit research organization that helps people reduce stress, discusses an experiment titled “Local and Nonlocal Effects of Coherent Heart Frequencies on Conformational Changes of DNA.” This study showed that thinking and feeling anger, fear, and frustration caused DNA to change shape according to thoughts and feelings. The DNA responded by tightening up and becoming shorter, switching off many DNA codes, which reduced quality expression. So we feel shut down by negative emotions, and our body feels this too. But here’s the great part: the negative shutdown or poor quality of the DNA codes was reversed by feelings of love, joy, appreciation, and gratitude! The researchers also found that HIV positive patients who had positive thoughts and feelings had 300,000 times more resistance to the disease than those without positive feelings. So the takeaway here is that when we operate in our normal love design—which is being made in God’s image (Gen. 1:26)—we are able to change the shape of our DNA for the better.

So when we make a poor-quality decision—when we choose to engage toxic thoughts (for example, unforgiveness, bitterness, irritation, or feelings of not coping)—we change the DNA and subsequent genetic expression, which then changes the shape of our brain wiring in a negative direction. This immediately puts the brain into protection mode, and the brain translates these poor-quality, toxic thoughts as negative stress.

This stress then manifests in our bodies. But the most exciting part of this study was the hope it demonstrated because the positive attitude, the good choice, rewired everything back to the original healthy positive state. These scientists basically proved we can renew our minds.


Stress stage one is normal. This is our alert state that keeps us focused and conscious and is the state we are in when we are thinking in alignment with God. Stress stage two and stage three, however, are our mind and body’s response to toxic thinking—normal stress gone wrong. Even a little bit of these negative levels of stress from a little bit of toxic thinking has far-reaching consequences for mental and physical health.

The dictionary defines stress as “a condition typically characterized by symptoms of mental and physical tension or strain, as depression or hypertension, that can result from a reaction to a situation in which a person feels threatened, pressured, etc.”

Synonyms for stress include anxiety, nervousness, fearfulness, apprehensiveness, impatience, fear, tenseness, and restlessness.

Reaction is the key word here. You cannot control the events or circumstances of your life, but you can control your reactions. And controlling those reactions is the difference between healthy minds and bodies and sick minds and bodies.

Here are just a few statistics confirming that 75 to 98 percent of mental and physical illness comes from one’s thought life:

  • A study by the American Medical Association found that stress is a factor in 75 percent of all illnesses and diseases that people suffer from today.
  • The association between stress and disease is a colossal 85 percent.
  • The International Agency for Research on Cancer and the World Health Organization have concluded that 80 percent of cancers are due to lifestyle and not genetics, and this is a conservative number.
  • According to Dr. Bruce Lipton, a scientist who has made great strides in understanding the effect of our thinking on our brain, gene disorders like Huntington’s chorea, beta thalassemia, and cystic fibrosis, to name a few, affect less than 2 percent of the population. This means the vast majority of the world’s population comes into this world with genes that should enable them to live happy and healthy lives. Lipton says a staggering 98 percent of diseases are related to lifestyle choices—in other words, our thinking.
  • According to Dr. H. F. Nijhout,genes control biology and not the other way around.
  • According to W. C. Willett,only 5 percent of cancer and cardiovascular patients can attribute their disease to hereditary factors.
  • The American Institute of Health estimates that 75–90 percent of all visits to primary care physicians are for stress-related problems. Some of the latest negative stress statistics causing illness as a result of toxic thinking are eye-opening.

The main point of this chapter is that mind controls matter.

If we get this right, we have enormous potential to reach peak health. If we get it wrong, we will be our own worst enemies.

Chapter 1 Summary

  1. The debate in science is between the mind being what the brain does versus the brain doing the bidding of the mind.
  2. The correct view is that the mind is designed to control the body, of which the brain is a part, not the other way around.
  3. Our brain does not control us; we control our brain through our thinking and choosing.
  4. We can control our reactions to anything.
  5. Choices are real. You are free to make choices about how you focus your attention, and this affects how the chemicals, proteins, and wiring of your brain change and function.
  6. Research shows that DNA actually changes shape in response to our thoughts.
  7. Stress stage one is normal. Stress stage two and stage three, on the other hand, are our mind and body’s response to toxic thinking—basically normal stress gone wrong.
  8. Reaction is the key word here. You cannot control the events or circumstances of your life, but you can control your reactions.

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