The Science of Health: Based on Structure, Function, & Purpose: Biological Practice, Application, & Implementation
Edition: 2
Copyright: 2026
Edition: 2
Copyright: 2026
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$170.00 USD
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$140.00 USD
The concept of health can seem puzzling to those who only hold bits and pieces of information. But when studying the science of anything, the focus should always be on structure, function, and purpose—asking: What is it? How does it work? Why does it exist?
The Science of Health: Based on Structure, Function, & Purpose offers habit-changing insights into health by organizing content around three key, interconnected pillars:
The Digestive System, Food & Nutrients, and Physical Activity
Together, these elements form the foundation for understanding the science behind health. As you move through the chapters, you’ll be challenged to deepen your awareness of health through practice, application, and implementation of knowledge you gain.
By the end, you’ll have a new mindset about why we eat—ultimately transforming the way you think about and engage with digestion, nutrition, and exercise. In essence, this book takes you on a molecular and cellular journey into The Science of Health.
Students Served & Course Adoption
The Science of Health 2e is designed for a broad range of learners—from high school to college students and students enrolled in professional programs.
The text and accompanying resources can support courses in:
- Biology & Human Biology
- Nutrition & Consumer Nutrition
- Health & Wellness
- Anatomy & Physiology
- Allied Health & Professional Programs
- General Education Science Courses
- High School Biology, Health, and Life Science Courses
The materials are especially appropriate for courses that introduce students to the structure, function, and purpose of the human body of the human body while connecting scientific concepts to everyday health, nutrition, physical activity, and decision-making.
At the heart of The Science of Health 2e is the movement from knowing to doing. Students are encouraged to engage with content through three progressive stages: Practice → Application → Implementation
Students first practice concepts and skills, then apply their knowledge to real-world situations, and ultimately implement what they have learned through informed decisions and actions. This approach emphasizes the execution of knowledge—not simply what students know, but what they can do with what they know.
Whether used as a primary textbook, supplemental resource, or instructional companion, The Science of Health 2e can be adapted across educational levels while helping students connect scientific knowledge to everyday health, nutrition, physical activity, and lifelong decision-making.
About the Author
Preface
UNIT 1: THE WHAT, HOW, AND WHY OF HEALTH
Chapter 1: Welcome to the Science of Health
Section 1.1: Challenges We Still Face
Section 1.2: Why We Eat
Section 1.3: Change Your Mindset
Section 1.4: Health Goals
Section 1.5: So … Why?
Section 1.6: Why Science, Nutrition, and Health
Chapter 2: Prevention, Policy, and Profession
Section 2.1: Myths. Misconceptions. Misinformation
Section 2.2: Prevention. Cure. Treatment
Section 2.3: Policies. Procedures. Regulations
Section 2.4: Careers in the Field
UNIT 2: CELLS, CHOICES, AND CHEMICAL BALANCE
Chapter 3: Cells, Life, and the Science Behind the Body
Section 3.1: Knowledge of -ologies
Section 3.2: Hierarchy of Life
Section 3.3: The Thing About Cells
Chapter 4: Food Quality and Smart Choices
Section 4.1: Filler Foods
Section 4.2: Processed, Packaged, and Preserved
Section 4.3: Reading Food Labels
Section 4.4: Fresh, Raw, and Natural
Section 4.5: Nutrient Diversity
Chapter 5: Life’s Chemical Code
Section 5.1: Overconsumption and Underconsumption
Section 5.2: pH and Solubility
Section 5.3: Metabolism
Section 5.4: Enzymes
Section 5.5: Natural Versus Artificial Selection
UNIT 3: DIGESTION, ABSORPTION, AND GUT HEALTH
Chapter 6: Structure, Function, and Purpose of The Digestive System
Section 6.1: Why Do We Eat … Really?
Section 6.2: Digestive System Overview
Section 6.3: Structure of the Gastrointestinal Tract
Section 6.4: Function and Purpose of Digestion
Chapter 7: Nutrient Absorption and Digestive Conditions
Section 7.1: Mechanical and Chemical Digestion
Section 7.2: Adenosine Triphosphate Production
Section 7.3: Nutrient Absorption
Section 7.4: Metabolism of Nutrients
Section 7.5: Common Gastrointestinal Disorders
Section 7.6: Obesity, Dietary Fat, and Heart Disease
Section 7.7: Protein Imbalances
UNIT 4: WHAT IS IN YOUR FOOD
Chapter 8: From Food to Nutrients
Section 8.1: Food to Nutrients
Section 8.2: Macronutrients Versus Micronutrients
Section 8.3: Polymers and Monomers
Section 8.4: Douglas’s Hierarchy of Food Composition
Section 8.5: “Organic” Explained
Chapter 9: Macronutrients and Dietary Additions
Section 9.1: Carbohydrates
Section 9.2: Lipids
Section 9.3: Proteins
Section 9.4: Dietary Supplements
Section 9.5: Absorption of Macronutrients
Chapter 10: Micronutrients and Other Essentials
Section 10.1: Water and Electrolytes
Section 10.2: Minerals
Section 10.3: Vitamins
Section 10.4: Alcohol: Tonic or Toxin?
UNIT 5: MOVE WELL, LIVE WELL!
Chapter 11: Fitness and Wellness Foundations
Section 11.1: Wellness and Stress
Section 11.2: Importance of Physical Activity
Section 11.3: Low, Moderate, and Extreme Impact Activities
Section 11.4: Physical Fitness Physiology
Section 11.5: The Five Fitness Components
Chapter 12: Physical Activity in Practice
Section 12.1: Proper Posture, Form, and Technique
Section 12.2: The Science of Breathing
Section 12.3: The Purpose of Activity
Section 12.4: Energy Balance
Section 12.5: Water and Exercise
Chapter 13: Training for Growth and Performance
Section 13.1: Fitness Assessments
Section 13.2: Strength and Core
Section 13.3: Muscle Growth and Principles
Section 13.4: Nutrient Timing
Section 13.5: Muscular Fitness
Section 13.6: Aerobic Fitness
Section 13.7: Flexibility Benefits
Chapter 14: Injury, Recovery, and Longevity
Section 14.1: Recovery Importance
Section 14.2: Common Exercise Mistakes and Injuries
Section 14.3: Protecting Your Back
UNIT 6: FITNESS IN MOTION
Chapter 15: Endurance and Cardiovascular Conditioning
Section 15.1: Let’s Get Moving!
Section 15.2: Aerobics, Kickboxing
Section 15.3: Aquatic Training, Cycling
Section 15.4: High-Intensity Interval Training and Warm-Ups
Chapter 16: Strength, Stability, and Functional Training
Section 16.1: Body Conditioning
Section 16.2: Circuit and Peripheral Heart Action Training
Section 16.3: Stability and Bootcamp Training
Chapter 17: Flexibility and Mind–Body Integration
Section 17.1: Stretching
Section 17.2: Yoga
Section 17.3: Pilates
Section 17.4: Mind–Body Fitness
"The unseen threads that link us together sustain our existence, explain our connections, and define our destiny." — TS Douglas, 2016
Dr. TS Douglas is an educator, researcher, author, and health and fitness practitioner whose work bridges biology, nutrition, physical activity, and higher education. She holds a B.S. in Biology and an M.S. in Molecular, Cellular, & Microbial Biology from Chicago State University, as well as a Ph.D. in Educational Administration and Foundations of Higher Education from Illinois State University.
Dr. Douglas's scientific background includes research in immunology, molecular biology, developmental biology, and cellular science. Her doctoral research focused on improving biology education for nontraditional students in community college settings.
A lifelong advocate for health and fitness, Dr. Douglas has participated in running, cycling, aerial fitness, and strength training and has served as both a personal trainer and fitness instructor. These experiences shaped her belief that health is best understood through both scientific knowledge and practical application.
While teaching Nutrition at the City Colleges of Chicago, Dr. Douglas recognized a need for educational resources that more clearly connect nutrition recommendations to the biological systems and cellular processes that make health possible. This insight led to the development of her Structure, Function, and Purpose (SFP) framework and the publication of Cellular Nutrition (2018) and The Science of Health 2e (2025).
In The Science of Health, Dr. Douglas integrates biology, nutrition, and physical activity into a unified approach to health education. By exploring the structure, function, and purpose of the human body, she helps readers understand not only what supports health, but also how and why it does.
"Talent + Technique + Purpose + Action + Transformation = POWER"
— TS Douglas, 2022
The concept of health can seem puzzling to those who only hold bits and pieces of information. But when studying the science of anything, the focus should always be on structure, function, and purpose—asking: What is it? How does it work? Why does it exist?
The Science of Health: Based on Structure, Function, & Purpose offers habit-changing insights into health by organizing content around three key, interconnected pillars:
The Digestive System, Food & Nutrients, and Physical Activity
Together, these elements form the foundation for understanding the science behind health. As you move through the chapters, you’ll be challenged to deepen your awareness of health through practice, application, and implementation of knowledge you gain.
By the end, you’ll have a new mindset about why we eat—ultimately transforming the way you think about and engage with digestion, nutrition, and exercise. In essence, this book takes you on a molecular and cellular journey into The Science of Health.
Students Served & Course Adoption
The Science of Health 2e is designed for a broad range of learners—from high school to college students and students enrolled in professional programs.
The text and accompanying resources can support courses in:
- Biology & Human Biology
- Nutrition & Consumer Nutrition
- Health & Wellness
- Anatomy & Physiology
- Allied Health & Professional Programs
- General Education Science Courses
- High School Biology, Health, and Life Science Courses
The materials are especially appropriate for courses that introduce students to the structure, function, and purpose of the human body of the human body while connecting scientific concepts to everyday health, nutrition, physical activity, and decision-making.
At the heart of The Science of Health 2e is the movement from knowing to doing. Students are encouraged to engage with content through three progressive stages: Practice → Application → Implementation
Students first practice concepts and skills, then apply their knowledge to real-world situations, and ultimately implement what they have learned through informed decisions and actions. This approach emphasizes the execution of knowledge—not simply what students know, but what they can do with what they know.
Whether used as a primary textbook, supplemental resource, or instructional companion, The Science of Health 2e can be adapted across educational levels while helping students connect scientific knowledge to everyday health, nutrition, physical activity, and lifelong decision-making.
About the Author
Preface
UNIT 1: THE WHAT, HOW, AND WHY OF HEALTH
Chapter 1: Welcome to the Science of Health
Section 1.1: Challenges We Still Face
Section 1.2: Why We Eat
Section 1.3: Change Your Mindset
Section 1.4: Health Goals
Section 1.5: So … Why?
Section 1.6: Why Science, Nutrition, and Health
Chapter 2: Prevention, Policy, and Profession
Section 2.1: Myths. Misconceptions. Misinformation
Section 2.2: Prevention. Cure. Treatment
Section 2.3: Policies. Procedures. Regulations
Section 2.4: Careers in the Field
UNIT 2: CELLS, CHOICES, AND CHEMICAL BALANCE
Chapter 3: Cells, Life, and the Science Behind the Body
Section 3.1: Knowledge of -ologies
Section 3.2: Hierarchy of Life
Section 3.3: The Thing About Cells
Chapter 4: Food Quality and Smart Choices
Section 4.1: Filler Foods
Section 4.2: Processed, Packaged, and Preserved
Section 4.3: Reading Food Labels
Section 4.4: Fresh, Raw, and Natural
Section 4.5: Nutrient Diversity
Chapter 5: Life’s Chemical Code
Section 5.1: Overconsumption and Underconsumption
Section 5.2: pH and Solubility
Section 5.3: Metabolism
Section 5.4: Enzymes
Section 5.5: Natural Versus Artificial Selection
UNIT 3: DIGESTION, ABSORPTION, AND GUT HEALTH
Chapter 6: Structure, Function, and Purpose of The Digestive System
Section 6.1: Why Do We Eat … Really?
Section 6.2: Digestive System Overview
Section 6.3: Structure of the Gastrointestinal Tract
Section 6.4: Function and Purpose of Digestion
Chapter 7: Nutrient Absorption and Digestive Conditions
Section 7.1: Mechanical and Chemical Digestion
Section 7.2: Adenosine Triphosphate Production
Section 7.3: Nutrient Absorption
Section 7.4: Metabolism of Nutrients
Section 7.5: Common Gastrointestinal Disorders
Section 7.6: Obesity, Dietary Fat, and Heart Disease
Section 7.7: Protein Imbalances
UNIT 4: WHAT IS IN YOUR FOOD
Chapter 8: From Food to Nutrients
Section 8.1: Food to Nutrients
Section 8.2: Macronutrients Versus Micronutrients
Section 8.3: Polymers and Monomers
Section 8.4: Douglas’s Hierarchy of Food Composition
Section 8.5: “Organic” Explained
Chapter 9: Macronutrients and Dietary Additions
Section 9.1: Carbohydrates
Section 9.2: Lipids
Section 9.3: Proteins
Section 9.4: Dietary Supplements
Section 9.5: Absorption of Macronutrients
Chapter 10: Micronutrients and Other Essentials
Section 10.1: Water and Electrolytes
Section 10.2: Minerals
Section 10.3: Vitamins
Section 10.4: Alcohol: Tonic or Toxin?
UNIT 5: MOVE WELL, LIVE WELL!
Chapter 11: Fitness and Wellness Foundations
Section 11.1: Wellness and Stress
Section 11.2: Importance of Physical Activity
Section 11.3: Low, Moderate, and Extreme Impact Activities
Section 11.4: Physical Fitness Physiology
Section 11.5: The Five Fitness Components
Chapter 12: Physical Activity in Practice
Section 12.1: Proper Posture, Form, and Technique
Section 12.2: The Science of Breathing
Section 12.3: The Purpose of Activity
Section 12.4: Energy Balance
Section 12.5: Water and Exercise
Chapter 13: Training for Growth and Performance
Section 13.1: Fitness Assessments
Section 13.2: Strength and Core
Section 13.3: Muscle Growth and Principles
Section 13.4: Nutrient Timing
Section 13.5: Muscular Fitness
Section 13.6: Aerobic Fitness
Section 13.7: Flexibility Benefits
Chapter 14: Injury, Recovery, and Longevity
Section 14.1: Recovery Importance
Section 14.2: Common Exercise Mistakes and Injuries
Section 14.3: Protecting Your Back
UNIT 6: FITNESS IN MOTION
Chapter 15: Endurance and Cardiovascular Conditioning
Section 15.1: Let’s Get Moving!
Section 15.2: Aerobics, Kickboxing
Section 15.3: Aquatic Training, Cycling
Section 15.4: High-Intensity Interval Training and Warm-Ups
Chapter 16: Strength, Stability, and Functional Training
Section 16.1: Body Conditioning
Section 16.2: Circuit and Peripheral Heart Action Training
Section 16.3: Stability and Bootcamp Training
Chapter 17: Flexibility and Mind–Body Integration
Section 17.1: Stretching
Section 17.2: Yoga
Section 17.3: Pilates
Section 17.4: Mind–Body Fitness
"The unseen threads that link us together sustain our existence, explain our connections, and define our destiny." — TS Douglas, 2016
Dr. TS Douglas is an educator, researcher, author, and health and fitness practitioner whose work bridges biology, nutrition, physical activity, and higher education. She holds a B.S. in Biology and an M.S. in Molecular, Cellular, & Microbial Biology from Chicago State University, as well as a Ph.D. in Educational Administration and Foundations of Higher Education from Illinois State University.
Dr. Douglas's scientific background includes research in immunology, molecular biology, developmental biology, and cellular science. Her doctoral research focused on improving biology education for nontraditional students in community college settings.
A lifelong advocate for health and fitness, Dr. Douglas has participated in running, cycling, aerial fitness, and strength training and has served as both a personal trainer and fitness instructor. These experiences shaped her belief that health is best understood through both scientific knowledge and practical application.
While teaching Nutrition at the City Colleges of Chicago, Dr. Douglas recognized a need for educational resources that more clearly connect nutrition recommendations to the biological systems and cellular processes that make health possible. This insight led to the development of her Structure, Function, and Purpose (SFP) framework and the publication of Cellular Nutrition (2018) and The Science of Health 2e (2025).
In The Science of Health, Dr. Douglas integrates biology, nutrition, and physical activity into a unified approach to health education. By exploring the structure, function, and purpose of the human body, she helps readers understand not only what supports health, but also how and why it does.
"Talent + Technique + Purpose + Action + Transformation = POWER"
— TS Douglas, 2022