Preface
The scientific knowledge in the field of ‘sports nutrition’ is rapidly expanding,
increasingly providing specific recommendations where, in the recent past, only
general guidelines were available to help athletes achieve at their best. The
information currently available is increasingly specific to the sport, age, gender,
and conditioned capacity of the athlete. For instance, in the past we may have
recommended the consumption of water or a non-descript sports beverage to help an
athlete achieve and/or sustain a desired hydration state, but now we have a
recommendations for volume, temperature, electrolyte concentration and composition,
and energy substrate concentration and composition for different aspects of the
athletic endeavor, including what should be recommended before, during, and after
training/competition.
The science of sports nutrition is also changing long-held beliefs on how athletes
should eat to perform at their best. The belief that if a small amount of nutrient
is good for you, then more must be better is pervasive in sporting environments.
This belief is increasingly being unraveled with scientific information suggesting
that more than enough is not better than enough, with recent evidence suggesting
that excessive intakes of even water-soluble vitamins, once thought to be benign,
may increase disease risks. The heavy consumption of protein, long believed to be
the ‘magic’ ingredient in any athlete’s diet, is now put into proper perspective
with both limitations on how much is useful and optimal strategies for consumption.
Importantly, high consumption of protein invariably results in low consumption of
carbohydrate, which is also a key ingredient in athletic performance but
inappropriately feared my many as fat-producing. The old paradigm of ‘Calories-in’
- ‘Calories-out’ has been clarified, as we now have good evidence suggesting that
energy availability in real time is critically important and that randomly
satisfying the energy requirement is not sufficient. We have come to learn that
even an athlete who has satisfied energy needs in a 24-hour period may still be at
risk for hormonal and body composition problems if the timing of energy consumption
has resulted in periods of significant energy balance deficits. The paradigm for
energy intake has shifted to one that should encourage athletes to eat in a way
that dynamically satisfies energy expenditure. The endocrine system really does
work in real time. Imagine the pancreas waiting until day’s end to observe what and
how much food was consumed earlier in the day as a way of determining how much
insulin it should produce. It just doesn’t happen that way, but the traditional
‘calories-in’ – ‘calories-out’ strategy does precisely that. A key emphasis for
this book is, therefore, to break through our old understandings of how athletes
should eat and drink to optimize performance by providing the new science in a way
that it can be applied. Importantly, there are many new resources that have helped
in this endeavor, including recent key guiding publications that include: the joint
position statement on ‘Nutrition and Athletic Performance’ from the American
College of Sports Medicine, the Academy of Nutrition and Dietetics, and Dietitians
of Canada; the recently published IOC consensus on ‘Dietary Supplements and the
High-Performance Athlete’; the IOC consensus on ‘Relative Energy Deficiency in
Sport’; and several publications on the impact of within-day energy deficiency in
male and female athletes.
Ultimately, this book was written to make the science accessible and applicable to
undergraduate student majors of exercise science and others whose education will
bring them into the athletic arena. Nutrition has an impact on multiple areas,
including injury prevention and injury recovery, muscle and skeletal development,
exercise recovery, psychological sense of well-being, and general health and
illness resistance. Under ideal circumstances all members of the sports medicine
team, including sports nutritionists, exercise physiologists, sports medicine
physicians, sports psychologists, and athletic trainers should have some
understanding of how nutrition impacts their specific area. Therefore, while the
primary focus of this book is to help exercise science students understand the
science of sports nutrition, it can also help others on the sports medicine team
understand the scientific basis of important nutritional issues that impact athlete
health and performance. By doing so, it is hoped that this book can contribute to
the cohesiveness and functionality of the sports medicine team, to the ultimate
benefit of the athlete. This book is also likely to find other readers who have an
interest in athlete health and success, including parents and coaches.
Since an important goal of this book was to make the science accessible, easily
understood, and applicable, any reader accepted at a college/university should be
capable of reading and understanding the book contents. A number of courses are
taught at the undergraduate and/or beginning graduate level for which this book
would be appropriate, including courses with titles such as “Nutrition for Physical
Activity”, “Nutrition for Exercise Science”, and “Sports Nutrition” and related
titles. Assuming the student has been accepted into any field related to applied
science and public health, there should be no prerequisites needed to take a course
using this book.
An important goal of this book was to make it a comprehensive source of nutrition
information that relates to athletic needs. All chapters begin with a case study
providing a real-world example of the potential problems an athlete can face, with
logical and practical solutions that are reinforced with the information that
follows in each chapter. Throughout the book the chapters emphasize the science
while making the science accessible and applicable. This is true for each chapter,
with an introductory chapter that provides an overview of critical issues and
terms, common myths, an introduction to nutrients, and information on standards of
nutrient intake adequacy. Each topic covered in Chapter 1 is covered in greater
detail in subsequent chapters. Chapters 2, 3, and 4 cover the energy substrates
(carbohydrate, protein, and fat) with the same goal of breaking through myths by
providing the science in a way that demonstrates how to make the right
recommendations to athletes seeking to perform at their best. Chapters 5 (vitamins)
and 6 (minerals) break through many myths on vitamins and minerals, while providing
strategies to assure adequate intakes while avoiding deficiencies and/or
toxicities. Chapter 7 addresses the critically important issue of hydration and
related problems associated with consuming the wrong fluid in inappropriate volumes
and at times that fail to optimally satisfy need. Chapter 8 focuses on the
importance of assessing body composition rather than weight to better understand if
energy and nutrient needs are helping the athlete achieve a physique that will
enable improved performance. Chapter 9 provides information on how modifications in
nutrient intake can alter oxygen transport and utilization to working muscles, and
how doing the right things nutritionally can also help to improve muscle recovery
and reduce muscle soreness. Chapter 10 emphasizes that athletes of different ages
and genders may well have different nutritional needs. A failure to realize these
differences may compromise an athlete’s potential for optimal performance, and may
also predispose them to nutritional problems that could compromise health. Chapter
11 takes a close look at how athletes involved in different sports (i.e., power,
endurance, and team) may well face different nutritional needs that, unless
satisfied, could impact performance. Chapter 12 covers how travel and environmental
conditions can affect nutritional requirements, with strategies that can help to
lower nutritional risks. Chapter 13 expands on Chapters 5 and 6 by reviewing more
information on dietary supplements and aids that are intended to improve
performance. There are many myths uncovered in this chapter, which make it a must-
read for anyone working with athletes. Ideally, involvement in sporting activities
should be health enhancing, particularly if the right nutritional strategies are
followed. Chapter 14 addresses nutritional issues that are related to athlete
health, so that those who work with athletes have a better long-term view of how
the strategies that are followed today have implications for athlete health
tomorrow. The final book chapter, Chapter 15, focuses on practical issues related
to diet planning by pulling in the information provided earlier in the book that
answers this question: OK, now that I have the science, how should I eat to achieve
my goals? The chapter is filled with practical information that includes dietary
assessment strategies and practical information for how to satisfy needs in
different sports that have different natural breaks (ie. Half-time, etc.),
different training durations (marathoners need different nutrition strategies than
sprinters), and how to eat before, during, and after training. Each chapter closes
with a test-bank of 10 questions to help the reader be assured that they have
understood the critical issues presented in the chapter.
An important part of this book is the Appendix, which provides key reference
materials (Dietary Reference Intakes, Nutrient Content of high risk nutrients,
etc.), and also a sample Health History Questionnaire. The appendix also provides a
doorway to on-line resources, which include sample dietary analyses and nutrition
problem resolution strategies for both male and female athletes of different ages
and in different sports.
From beginning to end, “Nutrition for Exercise Science” is meant to provide the
reader with a comprehensive resource to help guide the nutritional guidance given
to athletes, and to know when it is appropriate to make a referral to a
credentialed health professional (eg. Registered Dietitian; Physician; Certified
Athletic Trainer; etc.) when the athlete’s condition warrants a referral.
It is with high hopes that you will find this book to be useful in your
professional endeavors.
Dan Benardot, PhD, RD, LD, FACSM
Professor of Nutrition, Emeritus. Benardot, Dan. (2019). ACSM's Nutrition for
Exercise Science. Preface
The scientific knowledge in the field of ‘sports nutrition’ is rapidly expanding,
increasingly providing specific recommendations where, in the recent past, only
general guidelines were available to help athletes achieve at their best. The
information currently available is increasingly specific to the sport, age, gender,
and conditioned capacity of the athlete. For instance, in the past we may have
recommended the consumption of water or a non-descript sports beverage to help an
athlete achieve and/or sustain a desired hydration state, but now we have a
recommendations for volume, temperature, electrolyte concentration and composition,
and energy substrate concentration and composition for different aspects of the
athletic endeavor, including what should be recommended before, during, and after
training/competition.
The science of sports nutrition is also changing long-held beliefs on how athletes
should eat to perform at their best. The belief that if a small amount of nutrient
is good for you, then more must be better is pervasive in sporting environments.
This belief is increasingly being unraveled with scientific information suggesting
that more than enough is not better than enough, with recent evidence suggesting
that excessive intakes of even water-soluble vitamins, once thought to be benign,
may increase disease risks. The heavy consumption of protein, long believed to be
the ‘magic’ ingredient in any athlete’s diet, is now put into proper perspective
with both limitations on how much is useful and optimal strategies for consumption.
Importantly, high consumption of protein invariably results in low consumption of
carbohydrate, which is also a key ingredient in athletic performance but
inappropriately feared my many as fat-producing. The old paradigm of ‘Calories-in’
- ‘Calories-out’ has been clarified, as we now have good evidence suggesting that
energy availability in real time is critically important and that randomly
satisfying the energy requirement is not sufficient. We have come to learn that
even an athlete who has satisfied energy needs in a 24-hour period may still be at
risk for hormonal and body composition problems if the timing of energy consumption
has resulted in periods of significant energy balance deficits. The paradigm for
energy intake has shifted to one that should encourage athletes to eat in a way
that dynamically satisfies energy expenditure. The endocrine system really does
work in real time. Imagine the pancreas waiting until day’s end to observe what and
how much food was consumed earlier in the day as a way of determining how much
insulin it should produce. It just doesn’t happen that way, but the traditional
‘calories-in’ – ‘calories-out’ strategy does precisely that. A key emphasis for
this book is, therefore, to break through our old understandings of how athletes
should eat and drink to optimize performance by providing the new science in a way
that it can be applied. Importantly, there are many new resources that have helped
in this endeavor, including recent key guiding publications that include: the joint
position statement on ‘Nutrition and Athletic Performance’ from the American
College of Sports Medicine, the Academy of Nutrition and Dietetics, and Dietitians
of Canada; the recently published IOC consensus on ‘Dietary Supplements and the
High-Performance Athlete’; the IOC consensus on ‘Relative Energy Deficiency in
Sport’; and several publications on the impact of within-day energy deficiency in
male and female athletes.
Ultimately, this book was written to make the science accessible and applicable to
undergraduate student majors of exercise science and others whose education will
bring them into the athletic arena. Nutrition has an impact on multiple areas,
including injury prevention and injury recovery, muscle and skeletal development,
exercise recovery, psychological sense of well-being, and general health and
illness resistance. Under ideal circumstances all members of the sports medicine
team, including sports nutritionists, exercise physiologists, sports medicine
physicians, sports psychologists, and athletic trainers should have some
understanding of how nutrition impacts their specific area. Therefore, while the
primary focus of this book is to help exercise science students understand the
science of sports nutrition, it can also help others on the sports medicine team
understand the scientific basis of important nutritional issues that impact athlete
health and performance. By doing so, it is hoped that this book can contribute to
the cohesiveness and functionality of the sports medicine team, to the ultimate
benefit of the athlete. This book is also likely to find other readers who have an
interest in athlete health and success, including parents and coaches.
Since an important goal of this book was to make the science accessible, easily
understood, and applicable, any reader accepted at a college/university should be
capable of reading and understanding the book contents. A number of courses are
taught at the undergraduate and/or beginning graduate level for which this book
would be appropriate, including courses with titles such as “Nutrition for Physical
Activity”, “Nutrition for Exercise Science”, and “Sports Nutrition” and related
titles. Assuming the student has been accepted into any field related to applied
science and public health, there should be no prerequisites needed to take a course
using this book.
An important goal of this book was to make it a comprehensive source of nutrition
information that relates to athletic needs. All chapters begin with a case study
providing a real-world example of the potential problems an athlete can face, with
logical and practical solutions that are reinforced with the information that
follows in each chapter. Throughout the book the chapters emphasize the science
while making the science accessible and applicable. This is true for each chapter,
with an introductory chapter that provides an overview of critical issues and
terms, common myths, an introduction to nutrients, and information on standards of
nutrient intake adequacy. Each topic covered in Chapter 1 is covered in greater
detail in subsequent chapters. Chapters 2, 3, and 4 cover the energy substrates
(carbohydrate, protein, and fat) with the same goal of breaking through myths by
providing the science in a way that demonstrates how to make the right
recommendations to athletes seeking to perform at their best. Chapters 5 (vitamins)
and 6 (minerals) break through many myths on vitamins and minerals, while providing
strategies to assure adequate intakes while avoiding deficiencies and/or
toxicities. Chapter 7 addresses the critically important issue of hydration and
related problems associated with consuming the wrong fluid in inappropriate volumes
and at times that fail to optimally satisfy need. Chapter 8 focuses on the
importance of assessing body composition rather than weight to better understand if
energy and nutrient needs are helping the athlete achieve a physique that will
enable improved performance. Chapter 9 provides information on how modifications in
nutrient intake can alter oxygen transport and utilization to working muscles, and
how doing the right things nutritionally can also help to improve muscle recovery
and reduce muscle soreness. Chapter 10 emphasizes that athletes of different ages
and genders may well have different nutritional needs. A failure to realize these
differences may compromise an athlete’s potential for optimal performance, and may
also predispose them to nutritional problems that could compromise health. Chapter
11 takes a close look at how athletes involved in different sports (i.e., power,
endurance, and team) may well face different nutritional needs that, unless
satisfied, could impact performance. Chapter 12 covers how travel and environmental
conditions can affect nutritional requirements, with strategies that can help to
lower nutritional risks. Chapter 13 expands on Chapters 5 and 6 by reviewing more
information on dietary supplements and aids that are intended to improve
performance. There are many myths uncovered in this chapter, which make it a must-
read for anyone working with athletes. Ideally, involvement in sporting activities
should be health enhancing, particularly if the right nutritional strategies are
followed. Chapter 14 addresses nutritional issues that are related to athlete
health, so that those who work with athletes have a better long-term view of how
the strategies that are followed today have implications for athlete health
tomorrow. The final book chapter, Chapter 15, focuses on practical issues related
to diet planning by pulling in the information provided earlier in the book that
answers this question: OK, now that I have the science, how should I eat to achieve
my goals? The chapter is filled with practical information that includes dietary
assessment strategies and practical information for how to satisfy needs in
different sports that have different natural breaks (ie. Half-time, etc.),
different training durations (marathoners need different nutrition strategies than
sprinters), and how to eat before, during, and after training. Each chapter closes
with a test-bank of 10 questions to help the reader be assured that they have
understood the critical issues presented in the chapter.
An important part of this book is the Appendix, which provides key reference
materials (Dietary Reference Intakes, Nutrient Content of high risk nutrients,
etc.), and also a sample Health History Questionnaire. The appendix also provides a
doorway to on-line resources, which include sample dietary analyses and nutrition
problem resolution strategies for both male and female athletes of different ages
and in different sports.
From beginning to end, “Nutrition for Exercise Science” is meant to provide the
reader with a comprehensive resource to help guide the nutritional guidance given
to athletes, and to know when it is appropriate to make a referral to a
credentialed health professional (eg. Registered Dietitian; Physician; Certified
Athletic Trainer; etc.) when the athlete’s condition warrants a referral.
It is with high hopes that you will find this book to be useful in your
professional endeavors.
Dan Benardot, PhD, RD, LD, FACSM
Professor of Nutrition, Emeritus
