Dedication
With deep appreciation, this book is dedicated to the late Dr. Ray Peat, whose exceptional health research and generous support have restored the metabolic health of many, including my own.
Raymond Franklin Peat (1936-2022), a distinguished American researcher with a Ph.D. in biology, devoted over five decades to studying the interactions of nutrition, hormones, and health. His pioneering work on diet, thyroid function, progesterone, pregnenolone, and related hormones has left an indelible impact on these fields and positively influenced the lives of numerous individuals struggling with metabolic health issues.
In my early twenties, I suffered from hypothyroidism, a severe form of slow metabolism that caused a range of symptoms including chronic fatigue, severe digestive issues, muscle pain, headaches, low blood sugar, eczema, allergies, and hormonal imbalances among others. Fortunately, my encounter with Dr. Peat marked the turning point in my struggle with this condition.
Learning about his work gave me the essential roadmap I needed to restore my metabolic function. Dr. Peat introduced me to his unique treatment protocol, which included diet adjustments, the right thyroid medication, and hormonal support supplements like progesterone and pregnenolone.
Inspired by my recovery, I pursued a degree in biochemistry at university and later established my website, biochemnordic.com. Through my website and books, I now share Dr. Peat’s health principles.
In this book, I will explore the pro-metabolic dietary principles I learned from Dr. Peat, highlighting their role in boosting the metabolic rate and improving thyroid health.
Dr. Peat’s dietary principles are not merely a quick fix but a comprehensive nutritional lifestyle. By learning how to support your metabolism with the right foods, you can reduce stress, inflammation, aging, and disease.
My goal with this book is to cover all significant aspects of Dr. Peat’s nutritional research, presenting a flexible and practical diet that avoids fanaticism and rigidity. This approach will help you easily integrate his nutritional advice into your daily routines.
It's important to note that this book reflects my interpretation of Dr. Peat's dietary approach. Others may apply his principles slightly differently than what is presented here.
I hope this book acts as a beacon for those navigating the complex world of health and nutrition, enabling them to embark on their journey toward metabolic healing using Dr. Peat’s dietary principles.
Benedicte Mai Lerche, MSc, PhD
August 2024
Introduction
The metabolic rate quantifies how swiftly we transform food into energy. Many people link a slow metabolic rate with weight gain and obesity; however, it's critical to recognize that a very slow metabolism is a serious health condition known as hypothyroidism (Barnes & Galton, 1976, pp. 17-25).
As your metabolism decreases, each cell in your body generates less energy. In this low-energy state, the body loses structure and control, which can allow harmful degenerative processes to unfold (Peat R., Generative Energy, 2001a, pp. 1-5).
While a slow metabolism often results in weight gain, it can also lead to more serious health issues, such as chronic fatigue, digestive problems, hair and skin issues, hormonal imbalances as well as stress, inflammation, premature aging, and much more (Barnes & Galton, 1976, pp. 20-25).
The dietary principles outlined in this book are tailored for anyone seeking to enhance their metabolic rate through a scientifically supported dietary approach.
The diet advice presented in this book is drawn from Dr. Peat's distinctive nutritional research, which spanned over five decades.
Dr. Peat’s nutritional principles are designed to shift the body into a higher metabolic state, fostering repair, healing, and vibrant health.
He emphasized that many traditional and health-focused diets often contain foods that directly suppress the metabolic rate.
Upon my initial interaction with Dr. Peat, he advised me to avoid many foods commonly regarded as healthy such as polyunsaturated fats, beans, lentils, nuts, seeds, soy products, and raw vegetables from the cabbage family (Peat R., Generative Energy, 2001a, p. 75; Peat R., Nutrition for Women: 100 Short Articles, 2001d, p. 17).
The nutritional landscape is fraught with misconceptions that lack a solid basis in true biochemistry.
Frequent claims such as "sugar is poison," "milk is only for children," and "saturated fats cause heart disease," are often made without a scientifically sound explanation of how these foods impact the health of the body.
It is important to note that this book is not a cookbook; rather, its goal is to dispel many misconceptions about diet and demonstrate how adhering to Dr. Peat's nutritional guidelines can boost your metabolism.
Since Dr. Peat's dietary guidelines differ significantly from other advice, I will thoroughly elucidate the rationale behind each of his dietary recommendations.
Prepare yourself for a book that will fundamentally challenge everything you thought you knew about diet and health.
By the end of this book, you should be equipped to eliminate foods from your diet that inhibit your metabolism and instead base your meals on pro-metabolic combinations of the right types of food.
Although Dr. Peat has not detailed a specific diet plan, his nutritional recommendations have evolved over the years, and currently, those who adhere to his principles refer to it as the “Ray Peat diet.”
Before exploring these dietary principles, it's crucial to discuss key aspects of metabolism, which is the focus of the first chapter of this book.
The book is structured as follows:
Chapter 1: This chapter delves into essential aspects of metabolism, detailing the function of the thyroid gland and how the active thyroid hormone controls your metabolic rate. You'll learn about common symptoms of a sluggish metabolism, the best methods for testing your metabolic rate, and the causes and triggers of hypothyroidism.
Chapter 2: In this crucial chapter, I examine why polyunsaturated fats, often touted as healthy, actually pose significant risks to your health and thyroid function. You'll discover how these fats became mislabeled as healthy, their role in severely suppressing metabolism, and their contribution to obesity. Additionally, I discuss the benefits of saturated fats, which improve health and enhance metabolic function.
Chapter 3: This chapter explains how maintaining stable blood sugar amplifies the metabolic rate and examines the varied impacts of different carbohydrates on blood sugar and digestion. As you progress through this chapter, your perception of sugars, fruits, starches, whole grains, and fiber will transform. Ultimately, you'll gain profound insights into which carbohydrates boost metabolism and which ones predispose you to obesity.
Chapter 4: This chapter emphasizes the importance of consuming high-quality protein every day. You'll learn why many plant-based and some animal-based proteins can harm your health and hinder metabolic function. Additionally, you'll discover why excessive meat consumption may not be suitable for adults. By the end of this chapter, you will be able to select the best types of protein for optimal liver and metabolic function.
Chapter 5: In this chapter, I explore why consuming sufficient salt is particularly important for people with a slow metabolic rate. You'll discover how salt prevents water retention and high blood pressure, contrary to popular misconceptions. I also explain the types of salt and spices that align with the principles of the “Ray Peat diet.”
Chapter 6: This chapter focuses on beverages, explaining why excessive water intake can be detrimental to your health. It discusses the benefits of caffeine, the consumption of coffee and tea, and which types of alcoholic drinks are acceptable.
Chapter 7: This chapter explores food additives, emphasizing their role as contributors to inflammation and disease. You'll gain insight into various common food additives and understand how they harm your body.
Chapter 8: This chapter summarizes key points about fats, carbohydrates, and protein, guiding you in combining foods optimally for stable blood sugar and a higher metabolic rate. You'll learn why frequent eating and a bedtime meal can lower stress and improve sleep.
Chapter 9: The final chapter goes beyond diet, outlining other aspects of Dr. Peat’s health philosophy for healing metabolism, including thyroid replacement therapy, hormonal support compounds, nutritional supplements, light therapy, and more.
Chapter 1: Metabolism
What is Metabolism
To fully understand Dr. Peat’s pro-metabolic diet, it's essential to first grasp the key facets of metabolism. This chapter is dedicated specifically to that purpose.
Metabolism involves all the chemical reactions within the body's cells that convert food into biological energy. This biological energy then powers essential cellular functions and reactions (Nava & Raja., 2022).
Chemically, metabolism refers to the process in which cells use oxygen (O2) to transform nutrients (food) into carbon dioxide (CO2), water (H2O), heat, and adenosine triphosphate (ATP). ATP serves as the body’s biological energy source (Barnes & Galton, 1976, p. 3; Vander, Sherman, & Luciano, 2001, pp. 619-620).
To exemplify, consider the metabolic process involving glucose, represented by the following equation (Vander, Sherman, & Luciano, 2001, pp. 619-620; Boston University School of Public Health, 2017):
The speed of metabolism, or the metabolic rate, determines how quickly the body converts food into energy. Individuals with a high metabolism burn a substantial number of calories, and their cells produce a significant amount of biological energy (ATP) (Barnes & Galton, 1976, pp. 18-19).
While many associate the metabolic rate primarily with weight management, Dr. Peat emphasized that a high metabolic rate is essential for maintaining good health. He explained the critical importance of biological energy (ATP) for maintaining the structure and function of the body's tissues and organs (Peat R., Generative Energy, 2001a, pp. 1-5).
Dr. Peat proposed that disease, inflammation, and degeneration arise when there's an imbalance between the body's energy production and the demands of its environment (Peat R., Generative Energy, 2001a, pp. 1-5).
This indicates that a slow metabolic rate, marked by low cellular energy levels, significantly contributes to the onset of harmful degenerative processes (Peat R., Nutrition for Women: 100 Short Articles, 2001d, p. 16).
The thyroid gland plays a pivotal role in regulating the speed of metabolism. Therefore, a reduced metabolic rate can also be termed low thyroid function, medically known as hypothyroidism.
In the following section, I will delve into crucial aspects of thyroid function and its relationship to metabolism.
Thyroid & Metabolism
Located in the front of the throat, the human thyroid gland (Figure 1.1) has a butterfly shape (Barnes & Galton, 1976, p. 3).
It is a small endocrine gland that produces and releases two hormones: triiodothyronine (T3), and thyroxine (T4) into the bloodstream. Collectively, T4 and T3 are known as the thyroid hormones (Society of Endocrinology, 2020).
Figure 1.1: A sketch of the human thyroid gland, illustrating its distinctive butterfly shape and its location at the front of the throat.
It is crucial to understand that T3 is the active thyroid hormone, which affects cells and regulates the metabolic rate, whereas T4 is a pro-hormone for T3 (Society of Endocrinology, 2020).
The thyroid gland secretes more T4 than T3 (American Thyroid Association, 2023a). Dr. Peat, explained that T4 and T3 are released in a ratio of about 3:1, which corresponds to 75% T4 and 25% T3 (Peat R., Generative Energy, 2001a, p. 73).
Once secreted by the thyroid gland, T4 can be converted to the active thyroid hormone T3 in other organs and tissues (Society of Endocrinology, 2020).
Most of this conversion occurs in the liver, which allows the liver to regulate the production of the active thyroid hormone T3 (Peat R., Generative Energy, 2001a, p. 73).
Because T3 regulates the speed of the metabolic rate that converts food into energy, T3 essentially controls the body’s energy (ATP) supply (Vander, Sherman, & Luciano, 2001, p. 267).
Hypothyroidism, characterized by low T3 levels, has devastating effects on the body, leading to various symptoms. This occurs because low cellular energy prevents tissues and organs from functioning optimally. In the following section, I will list the common symptoms associated with hypothyroidism.
Key Points – Metabolism & Thyroid Function:
- The metabolic rate measures how quickly food is converted into biological energy (ATP).
- The active thyroid hormone T3 controls the speed of metabolism.
- A slow metabolic rate can also be referred to as low thyroid function or hypothyroidism.
Symptoms of Slow Metabolism
A slow metabolic rate means that each cell in your body produces little energy. In a state of reduced metabolism, the body is more prone to harmful and degenerative processes rather than repair and healing (Peat R., Nutrition for Women: 100 Short Articles, 2001d, p. 16).
A slow metabolism affects various bodily functions, including energy levels, temperature regulation, heart rate, and overall hormonal health. Low T3 also affects organs such as the adrenals, pancreas, and reproductive glands (Barnes & Galton, 1976, p. 20). Therefore, a slow metabolic rate is significant not only for weight management but also for overall health.
The condition of slow metabolism, also known as low thyroid function or hypothyroidism, may affect various body systems, although not necessarily to the same extent in every individual. Therefore, the symptoms of slow metabolism can vary from person to person (Barnes & Galton, 1976, pp. 22-25).
Below is a list of common symptoms associated with a slow metabolic rate (Barnes & Galton, 1976, pp. 22-24; Wilson, 2015, p. 25; Peat R., Nutrition for Women: 100 Short Articles, 2001d, pp. 16-18; Peat R., From PMS to Menopause: Female Hormones in Context, 2001b, p. 78).
This list, while not exhaustive, provides an overview of the diverse symptoms related to slow metabolism (low thyroid function). It's important to remember that not all symptoms need to be present for you to have a metabolic problem.
Common low metabolic symptoms:
Fatigue: Feeling tired and lacking energy, even after getting adequate rest (chronic fatigue).
Headaches: Experiencing pressure headaches and migraines.
Hypoglycemia: Having low blood sugar, resulting in a need to eat frequently to avoid feeling faint and dizzy.
Weight changes: Experiencing unexplained weight gain or difficulty losing weight despite maintaining a healthy diet and regular exercise routine. Some individuals may also experience weight loss.
Low body temperature: Having cold intolerance, feeling excessively cold even in warm temperatures, and having cold hands and feet.
Reduced heart rate: Experiencing a slow heart rate (bradycardia) and decreased heart function.
Heart problems & disease: Experiencing heart pain, poor heart sounds, enlargement of the heart, palpitations, and hypertension.
Constipation: Experiencing slow digestion, difficulty passing stools, and infrequent bowel movements.
Digestive problems: Painful digestion, irritable bowel syndrome (IBS), as well as an overgrowth of bad bacteria and candida.
Dry skin: Having dry, rough, thin, pale skin that may be itchy and scaly, accompanied by conditions like eczema or skin infections.
Brittle hair & nails: Experiencing thinning of hair and nails, hair loss, changes in hair texture, and potential loss of the outer third of the eyebrows.
Muscle and joint pain: Experiencing muscle aches, stiffness, and joint pain not attributed to any specific injury or physical activity.
Carpal tunnel syndrome: Having pain, numbness, and tingling sensations in the hand, arms, and fingers (carpal tunnel syndrome).
Mood changes: Experiencing depression, anxiety, irritability, and mood swings.
Cognitive impairment: Having difficulty concentrating, poor memory, and decreased mental alertness (brain fog).
Hoarseness: Experiencing a deepening or hoarse voice, often accompanied by a sore throat.
Swelling: Experiencing water retention (edema), often with swelling or puffiness in the face, hands, feet, or ankles.
High cholesterol: Having elevated levels of cholesterol in the blood, even with a healthy diet and lifestyle.
Decreased libido: Experiencing a loss of interest in sexual activity and a reduced sexual drive.
Menstrual irregularities: Having irregular menstrual cycles, heavy menstrual bleeding, prolonged menstrual periods, painful menstruation, and experiencing symptoms of premenstrual syndrome (PMS) and polycystic ovaries (PCOS).
Infertility & miscarriage: Experiencing male and female infertility, with a higher chance of miscarriage in females.
Insomnia: Having problems falling asleep and/or waking up during the night.
Other symptoms: Poor vision, hearing loss, anemia, allergies, frequent colds, infections, orange calluses, inflammation, premature aging, and more.
Measure Your Metabolism
To assess a patient’s metabolic rate, doctors often perform blood tests to evaluate thyroid function, typically measuring levels of TSH (Thyroid Stimulating Hormone), T4 (thyroxine), and T3 (triiodothyronine). Other crucial tests include those for reverse T3 and thyroid antibodies.
You may have already undergone some of these tests and found your results to be within the so-called "normal" ranges.
It's crucial to understand that you can still have a low metabolism despite normal thyroid blood test results.
One reason is that the reference ranges for these blood tests are quite broad, allowing many individuals with symptoms of hypothyroidism to fall within these "normal" ranges. Dr. Peat explained the importance of distinguishing between the normal reference ranges for thyroid blood tests and the optimal levels for these tests, which are more indicative of true thyroid health.
Additionally, Dr. Peat pointed out that blood tests may not accurately reflect the true metabolic rate, as the cellular response to the active thyroid hormone T3 can be inhibited by anti-metabolic substances like polyunsaturated fats (Peat R., Generative Energy, 2001a, p. 72; Wilson, 2015, p. 28; Peat R., TSH, temperature, pulse rate, and other indicators in hypothyroidism, 2008a).
Dr. Peat recommended using a combination of thyroid function blood tests, pulse rate, and body temperature tracking, along with symptom monitoring, to more accurately gauge your metabolic rate.
Optimal metabolism is characterized by an oral temperature of approximately 98.6°F (37°C) and a pulse rate ranging from 80 to 85 beats per minute (Peat, 2001b, p. 76). (Peat, 2001b, p. 76).
It's essential to recognize that individuals with reduced thyroid function may compensate for their energy deficiency by producing high levels of stress hormones, such as cortisol and adrenaline. These hormones can elevate body temperature and pulse rate, potentially complicating the use of these metrics in evaluating the metabolic rate. (Peat, 2008, p. 5).
In my book, "Test Your Thyroid Function," you will discover essential information to help you interpret your thyroid blood test results and monitor your metabolism at home using pulse rate and body temperature. This book also explores many important aspects of metabolic health, including the autoimmune form of hypothyroidism known as Hashimoto's thyroiditis, reverse T3, how to prepare for your thyroid blood test, and much more. "Test Your Thyroid Function" is an indispensable resource for anyone looking to thoroughly understand and take control of their metabolic health.
Causes of Slow Metabolism
Dr. Peat identified several factors that can lead to slow metabolism. Three common causes include inadequate secretion of thyroid hormones by the thyroid gland (Sluggish Gland), ineffective conversion of T4 to active thyroid hormone T3 (Conversion Defect), or impaired cellular response to T3 (T3 Blockage) (Peat R., Generative Energy, 2001a, pp. 72-74; Wilson, 2015, pp. 24-28).
Dr. Peat's extensive research suggests that hypothyroidism usually arises from a combination of these factors. Regardless of the underlying cause, hypothyroidism ultimately leads to a deficiency of biological energy (ATP) (Peat R., Generative Energy, 2001a, pp. 2-3; Peat R., TSH, temperature, pulse rate, and other indicators in hypothyroidism, 2008a).
A sluggish thyroid gland:
An underactive thyroid gland is unable to produce sufficient amounts of the thyroid hormones T4 and T3. This deficiency might be attributed to the gland's intrinsic limitations.
However, other factors such as a diet high in polyunsaturated fats, undercooked cruciferous vegetables like raw cabbage, and excess estrogen can also contribute to reducing the hormonal output of the thyroid gland (Peat R., From PMS to Menopause: Female Hormones in Context, 2001b, pp. 155-156).
Estrogen is primarily regarded as a female hormone, but men produce it as well. According to Dr. Peat, controlled amounts of estrogen are essential for female ovulation and pregnancy (Peat R., From PMS to Menopause: Female Hormones in Context, 2001b, pp. 3-22).
However, excessive estrogen from endogenous sources (produced by the body) or exogenous sources (such as food or birth control pills) can have many negative effects. Dr. Peat explains that estrogen excess has a shock-like effect and contributes to stress, inflammation, aging, and hypothyroidism (Peat R., From PMS to Menopause: Female Hormones in Context, 2001b, pp. 3-22).
Food sources high in estrogen include beans, soybeans, lentils, and beer, among others (Medical News Today, 2023b; Peat R., Natural estrogens, 2008b).
Conversion defect:
Sometimes, people have high levels of T4 yet still experience symptoms of slow metabolism. This situation likely occurs due to inefficient conversion of the storage hormone T4 to the active thyroid T3 (Peat R., Generative Energy, 2001a, p. 74).
As previously noted, the liver is the primary organ responsible for converting T4 to T3. Consequently, compromised liver function can lead to hypothyroidism (Peat R., Generative Energy, 2001a, p. 73).