Nutrition for Health, Fitness and Sport 11th Edition

Book Preface

L E A R N I N G O B J E C T I V E S
After studying this chapter, you should be able to:
1. Explain the role of both genetics and environment, particularly nutrition
and exercise, in the determination of optimal health and successful sport
performance.
2. List each of the components of health-related fitness and then identify the
potential health benefits of an exercise program designed to enhance both
aerobic and musculoskeletal fitness.
3. Define sports-related fitness and compare it to health-related fitness, noting
similarities and differences.
4. List the seven principles of exercise training and explain the importance of
each.
5. List the 12 guidelines underlying the Prudent Healthy Diet and discuss, in
general, the importance of proper nutrition to optimal health.
6. Understand the importance of proper nutrition, including the role of dietary
supplements as ergogenic aids, to sports performance.
7. Define nutritional quackery and understand the various strategies you can
use to determine whether claims regarding a dietary supplement are valid.
8. Explain what types of research have been used to evaluate the relationship
between nutrition and health or sport performance, and evaluate the pros
and cons of each type.

There are two major focal points of this book. One is the role that nutrition, complemented by physical activity and exercise, may play in the enhancement of one’s health status. The other is the role that nutrition may play in the enhancement of fitness and sports performance. Many individuals today are physically active, and athletic competition spans all ages. Healthful nutrition is important throughout the life span of the physically active individual because suboptimal health status may impair training and competitive performance. In general, as we shall see, the diet that is optimal for health is also optimal for exercise and sports performance. Nutrition, fitness, and health. Health care in most developed countries has improved tremendously over the past century. Although some rather rare diseases, such as Ebola, are a cause for concern, primarily because of the dedicated work of medical researchers we no longer fear the scourge of major acute infectious diseases such as polio, smallpox, or tuberculosis. However, we have become increasingly concerned with the treatment and prevention of chronic diseases. The World Health Organization (WHO) indicates that chronic diseases are now the major cause of death and disability worldwide. According to the U.S. Department of Health and Human Services (HHS), unhealthy eating and physical inactivity are leading causes of death in the United States. Given with rank in parentheses, they include (1) diseases of the heart, (2) cancer, (3) stroke, (4) chronic lung diseases, (6) diabetes, (8) Alzheimer’s disease, and (9) chronic kidney diseases. These diseases cause more than 85 percent of all deaths, and
this figure is destined to rise as the U.S. population becomes increasingly older, particularly during the first quarter of this century when the baby boomers of the 1940s and 1950s reach their senior years. The two primary factors that influence one’s health status are genetics and
lifestyle. According to Simopoulos, all diseases have a genetic predisposition. The Human Genome Project, which deciphered the DNA code of our 80,000 to 100,000 genes, has identified various genes associated with many chronic diseases, such as breast and prostate cancer. Genetically, females whose mothers had breast cancer are at increased risk for breast cancer, while males whose fathers had prostate cancer are at increased risk for prostate cancer. Completion of the Human Genome Project is believed to be one of the most significant medical advances of all time.

Although multiple genes are involved in the etiology of most chronic diseases and research regarding the application
of the findings of the Human Genome Project to improve health is still in its initial stages, the future looks bright. For individuals with genetic profiles predisposing them to a specific chronic disease, such as cancer, genetic therapy eventually may provide an effective treatment or cure.

Although genetic influences may play an important role predisposing an individual to a chronic disease, so, too, does lifestyle. The CDC notes that although chronic diseases are among the most common and costly health problems, they are also among the most preventable by adopting a healthy lifestyle. Over the years, scientists in the field of epidemiology have identified a number of lifestyle factors considered to be health risks; these lifestyle factors are known as risk factors. A risk factor is a lifestyle behavior that has been associated with a particular disease, such as cigarette smoking being linked to lung cancer. A major risk factor is being overweight or obese, a condition which affects almost two-thirds of Americans and is increasing worldwide.

The Department of Health and Human Services recently listed the leading lifestyle-related causes of premature death in the United States. The combination of an unhealthy diet and physical inactivity, which may contribute to being overweight or obese, was ranked as the leading cause, followed by tobacco use and alcohol abuse.

In a recent review, Hall noted that our genes harbor many secrets to a long and healthy life but also noted that genes alone are unlikely to explain all the secrets of longevity. The role of a healthful diet and exercise are intertwined with your genetic profile. What you eat and how you exercise may influence your genes. Epigenetics is a relatively new field of research involving the role of the epigenome, a structure located just outside the genome that may activate or deactivate DNA and subsequent genetic and cellular activity. Cloud noted that various factors in our environment, such as substances in the foods we eat, may interact with the epigenome and thus modify cell functions—either in a positive or negative manner. Exercise, as noted later, also stimulates release of substances from muscle cells that may affect the epigenome. Cloud notes that comparable to the Human Genome Project, a Human Epigenome Project is under way, 2 CHAPTER 1 Introduction to Nutrition for Health, Fitness, and Sports Performance www.mhhe.com/williams11e 3 and epigenetics may eventually lead to many beneficial health-related applications.

For example, if personal genetic code indicates that your genetic profile predisposes you to certain forms of cancer, and if your genetic profile indicates that you will respond favorably to specific nutritional or exercise interventions, then a preventive diet and an exercise plan may be individualized for you. Genomics represents the study of genetic material in body cells, and the terms nutrigenomics and exercisenomics have been coined to identify the study of the genetic aspects of nutrition and exercise, respectively, as related to health benefits. Sportomics  involves study of the metabolicresponse of the athlete in an actual sport environment, not in a laboratory. Treatment of chronic diseases is very expensive. Foreseeing a financial health-care crisis associated with an increasing prevalence of such diseases during the first half of this century, most private and public health professionals have advocated health promotion and disease prevention as the best approach to address this potential major health problem. Martinez-Perez and others note that with more than 1 billion smart phones around the world, the use of various applications for health promotion has great potential. The HHS, beginning in the 1980s, has published a series of reports designed to increase the nation’s health; the latest version is entitled Healthy People 2020: National Health Promotion/Disease Prevention Objectives. Physical activity/fitness and overweight/obesity are two of the major focus areas. These reports emphasize
that lifestyle behaviors that promote health and reduce the risk of chronic diseases are basically under the control of the individual. The role of diet and exercise in health promotion has become a worldwide priority, as documented in the WHO report Global Strategy on Diet, Physical Activity and Health. The guidelines presented in these reports underlie the recommendations presented in this book. For both reports, see web addresses below.

As we shall see, proper exercise and proper nutrition, both individually and combined, may reduce many of the risk factors associated with the development of chronic diseases. These healthful benefits will be addressed at appropriate points throughout the book. Nutrition, fitness, and sport. Sport is now most commonly defined as a competitive athletic activity requiring skill or physical prowess, for example, baseball, basketball, soccer, football, track, wrestling, tennis, and golf. As with health status, athletic ability and subsequent success in sport are based primarily upon genetics and epigenetics. In a review of epigenetics in sport, Ehlert and others note that natural genetic endowment with characteristics important to a specific sport must be maximized through epigenetic modifications by appropriate type and amount of training. To be successful at high levels of competition, athletes must possess the appropriate biomechanical, physiological, and psychological genetic characteristics associated with success in a given sport. International-class athletes have such genetic traits. In recent reviews, Tucker and others highlighted the genetic basis for elite running performance while Eynon and others discussed the role of genes for elite power and sprint performance. Moreover, Wolfarth and others have assembled a human gene map for performance and health- related fitness.

To be successful at high levels of competition, athletes must also develop their genetic characteristics maximally through proper biomechanical, physiological, and psychological coaching and training. Whatever the future holds for genetic enhancement of athletic performance, specialized exercise training will still be the key to maximizing genetic potential for a given sport activity.

Training programs at the elite level have become more intense and individualized, sometimes based on genetic predispositions. Modern scientific training results in significant performance gains, and world records continue to improve. David Epstein, in his book The Sports Gene, provides a fascinating account of the role both genes and the training environment play relative to elite sport performance. Proper nutrition also is an importantcomponent in the total training program of the athlete. Certain nutrient deficiencies can seriously impair performance, whereas supplementation of other nutrients may help delay fatigue and improveperformance. Over the past 50 years, research has provided us with many answers about the role of nutrition in athletic performance, but unfortunately some findings have been misinterpreted or exaggerated so that a number of misconceptions still exist.

The purpose of this chapter is to provide a broad overview of the role that exercise and nutrition may play relative to health, fitness, and sport, and how prudent recommendations may be determined. More detailed information regarding specific relationships of nutritional practices to health and sports performance is provided in subsequent chapters.

Content

CHAPTER ONE Introduction to Nutrition for Health, Fitness,
and Sports Performance 1
CHAPTER TWO Healthful Nutrition for Fitness and Sport:
The Consumer Athlete 37
CHAPTER THREE Human Energy 90
CHAPTER FOUR Carbohydrates: The Main Energy Food 125
CHAPTER FIVE Fat: An Important Energy Source during Exercise 175
CHAPTER SIX Protein: The Tissue Builder 223
CHAPTER SEVEN Vitamins: The Organic Regulators 277
CHAPTER EIGHT Minerals: The Inorganic Regulators 327
CHAPTER NINE Water, Electrolytes, and Temperature Regulation 370
CHAPTER TEN Body Weight and Composition for Health and Sport 428
CHAPTER ELEVEN Weight Maintenance and Loss through Proper Nutrition
and Exercise 476
CHAPTER TWELVE Weight Gaining through Proper Nutrition and Exercise 539
CHAPTER THIRTEEN Food Drugs and Related Supplements 565