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Introduction to Sports Nutrition
The idea of nutrition for sports is by no means novel. Arguably, it dates
back to at least 400 B.C., when Hippocrates linked diet, activity, and human
well-being. In fact, early Olympians consumed a high quantity of meat,
believing that certain foods fueled performance. In addition, Roman
legionaries were fed planned diets in preparation for traveling long distance
or when engaging in specific combat situations as dictated by battle plans.
With this history in mind, however, modern nutritional science dates back
less than 100 years, beginning with the isolation of the first vitamin, thi-
amine (B1) in 1926. The following decades focused on the discovery of the
micronutrient deficiencies associated with certain medical conditions. This
progress was followed by single-nutrient focused (e.g., saturated fat, low fat,
sugar) investigations, the introduction of fortified foods, and malnutrition
research, which eventually evolved to our contemporary emphasis on diet
quality (7). Thus, the current knowledge supporting elite athletes’ dietary practices stems from
the information collected and analyzed in the last century.
Interestingly, the consumption of various alcoholic beverages during and before competi-
tion was believed to enhance performance, and early Olympians, even in the early 20th century,
used alcohol as an “ergogenic aid” (4, 14). Today, we know its negative effects on performance,
recovery, protein synthesis, metabolism, and the nervous system (11, 12). During the 20th century,
novel investigations analyzed macronutrients relations to performance. One of the first studies
in the era of modern nutritional science analyzed the roles of carbohydrates and fats in pro-
viding energy during exercise, examining the concept of the energy continuum. Today, scientists
still seek to elucidate the effects of the same macronutrients on sports performance by
manipulating the impact of timing, quantity, and nutrient types on different aspects of sports
performance and recovery.
Modern technology and methodology have provided a much better understanding of
biochemistry and the important relationships between nutrients and health, and fitness and
performance; however, much of current practices today do not originate in the lab but arise
from the experimentation of athletes and coaches. Diet modification, competition-specific
practices, and even supplements and ergogenic aids have historical links with sports. However,
with all the modern advancements in science and technology, a definitive diet for sport, fitness,
or health has proved elusive. Genetic diversity, cultural differences, and daily experiences all
present variables to a single dietary strategy for all humans in a homogenous group, athletes
or otherwise.
Even the definition of diet has nuances: does it signify a habitual intake of nutrients or
an acute adjustment to those habits? Do special reasons for specific intakes exist, or are they
associated with a seasonal occurrence, inclusive of nutritional periodization? Seemingly, numer-
ous factors influence the food and drink a given person consumes at a given time. The idea of
sports nutrition includes this concept, as the diet of an athlete or fitness enthusiast may require
adjustments specific to the environment he or she is exposed to and the subsequent internal
Chapter 1 NCSF Sport Nutrition
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DEFINITIONS
Ergogenic aid –
Any ingested or employed element used for the specific purpose of improving performance.
Supplements –
Dietary product used to supplement a deficiency in the diet (e.g., multi-mineral/vitamin pills).
Introduction to Sport Nutrition
responses that occur with the exposure. But nutrition differs from diet. A diet con-
sists of nutrient and non-nutrient intakes, consumed by the mouth. Nutrition
involves all physiological processes that happen after the food or drink enters
the body to nourish cells and tissues, including responses of the digestive,
endocrine, circulatory, and excretory systems and the resultant metabolism.
Definitions of DIET
a: food and drink regularly provided or consumed
• a diet of fruits and vegetables
• a vegetarian diet
b: habitual nourishment
• links between diet and disease
c: the kind and amount of food prescribed for a person or
animal for a special reason
• was put on a low-sodium diet
d: a regimen of eating and drinking sparingly so as to reduce one’s weight
• going on a diet
A nutrient is a substance that nourishes an organism and
performs one or more functions. Nutrients are classified into two
primary categories: energy-yielding nutrients (EYN) and non-
energy yielding nutrients (NEYN). EYN and NEYN are further
broken down by chemical specificity into carbohydrates, fats, and
proteins, and vitamins, minerals, and water. All humans need
these nutrients for homeostasis; if any nutrient is missing, prob-
lems will exist in one or more of the life pathways. These pathways
tend to be divided into nutrients that promote growth and devel-
opment, provide energy, and regulate metabolic function.
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1 Ingestion
2 Digestion
3 Absorption
4 Circulation
5 Assimilation
6 Elimination
Stages ofNutrition
Vitamins Minerals
ENERGY-YIELDING NUTRIENTS NON-ENERGY YIELDING NUTRIENTS
Proteins – amino acids
Fats – fatty acids and glycerol
DEFINITIONS
Nutrient –
Any substance that provides nourishment to the body and helps maintain homeostasis of all bodily systems.
Energy-yielding nutrients –
Nutrients which yield usable energy in the form of calories; in -cludes carbohydrates, protein, and fat (non-nutrient alcohol contains 7 kcal).
Non-energy yielding nutrients –
Nutrients which do not contain calories but are still essential to bodily functions; includes water, minerals and vitamins.
Water
Carbohydrates – glucose, (preferred energy
source) fructose and galactose
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Therefore, a nutritious diet would be defined as one that regularly meets all of the body’s
macronutrient and micronutrient demands. Based on this definition, it would seem easy to
compose a nutritious diet for all humans. However, no single perfect diet exists for everyone.
Whereas domestic animals often eat the same foods every day, humans are omnivorous and
present diverse factors that affect nutritional needs. Certainly, some proposed diets suggest
everyone follow a particular nutrient prescription to attain optimal nutrition and body weight,
but if that were the case, only one diet book and diet would exist. Basic logic would suggest a
250 lb. NFL player would not have the same needs as a 142 lb. Olympic marathoner, even though
they would both qualify as athletes. Correspondingly, dietary strategies for weight loss do not
reflect the same nutrient makeup used for weight gain; even if, broadly speaking, both concern
themselves with the same areas of focus. Therefore, any diet’s nutrient composition should
reflect the goals of the diet as they pertain to health, fitness, and performance.
Eating for health should be simple: consume a variety of nutrients to establish a balance in
nutrition that provides for sufficiency without excess, relative to daily caloric expenditure.
Nonetheless, most people fail to satisfy this basic obligation. Part of the issue lies in the fact that
most people do not know how to put together a balanced diet, and many people are already
overweight and physically inactive, with just as many having one or more diseases. Including
these propositions exposes the complications in what seemed to be a simplistic strategy for all.
Developing a fitness-related diet may represent part of the solution to being overweight and
physically inactive, but additional goals tend to present additional nuances. Is the goal to be
lean, muscular, strong, or to attain high levels of cardiorespiratory fitness? Each chosen aim
presents a change in the energy composition and nutrient balance needed for success. Addi-
tionally, the targets in many fitness-related programs are associated with caloric expenditure,
but this is the opposite of the goals of sports nutrition. Whereas fitness programs are written
to maximize expended energy, in sports, the emphasis may be placed on sparing energy to make
it through a competition or tolerate a higher training volume. Therefore, the first step in estab-
lishing a nutritional strategy is identifying the diet’s ultimate ambitions.
Factors that Affect Nutrition A variety of factors determine the nutritional make-up of a diet and
influence the timing of nutrient consumption. These can be divided into
primary and secondary factors. Primary factors affect resting and activity
(metabolic) homeostasis. Secondary factors tend to be those associated
with culture, experience, and education.
To identify relevant primary factors, a process of evaluation must occur
in order to detect any health-related issues, such as the presence of genetic
tendency to disease or medical conditions, current deficiencies, and disordered
eating patterns. In addition, the assessment should evaluate anthropometrics,
family history, current behaviors, and activity status. Lastly, the fitness or
performance-related goals need to be evaluated for caloric demands, energy-
system specificity, and recovery needs of the athlete or fitness enthusiast.
Secondary factors include those that affect choices and influence behav-
iors. These tend to be more difficult to measure, as they are rooted in
established habits associated with interpersonal development. Socio economic Culture, experience, and education can all have an impact on nutritional adequacy for health or performance.
DEFINITIONS
Macronutrient –
Nutrients that are consumed in relatively greater quantities to prevent deficiencies and maintain optimal bodily function; includes carbo -hydrates, protein, fat and water.
Micronutrient –
Nutrients that are consumed in relatively small quantities to prevent deficiencies and maintain optimal bodily function; includes vitamins and minerals.
status, where one was raised geographically, who and what a person was exposed to, cultural
and family traditions, and personal efficacy all contribute as dietary influencers. Whereas
primary factors seem to be most relevant, secondary factors should not be disregarded. Rather,
identifying and understanding the influence they present makes it easier to manage them. A
very important concept in sports and fitness nutrition is that food plays a part in the body’s
pleasure system. Therefore, food and drink must be palatable, meet the daily demands of
stress, and also contribute to an acceptable quality of life.
Future Direction of Nutrition Science Individuals respond differently to diets due
to genetic variations that influence how dietary
components are absorbed, metabolized, and
utilized. Nutrigenetics and nutrigenomics
represent emerging areas in nutrition
science and shed light into the interactions
between diets and genetic and genomic varia-
tions. These fields are poised to be essential
tools of sports nutrition, set to improve evi-
dence-based, precise nutritional strategies in
the near future. While these two terms tend to
be used interchangeably, they represent distinct branches of nutrition science. Nutrigenetics
investigates the action of genetic variation, particularly single nucleotide polymorphism (SNP),
on nutrients and diets. Nutrigenomics on the other hand, studies the way nutrients affect
genome-wide expressions, metabolic pathways, and homeostatic control (8). Completion
of the Human Genome Project in 2003 revealed the genetic blueprint of human
beings, marking the turning point for nutrition science and optimization of sports
nutrition, in terms of personalizing and predicting what individual athletes need
to reach peak performance goals. The identification of obesity-associated gene
variants exemplifies this work. People who carry these genes are 22-30%
more likely to be obese than people who do not. Moreover, certain
food/drink choices may exacerbate the obesity risk of individuals carrying
fat-mass and obesity-associated gene markers (9,10); however, healthy lifelong
nutritional strategies and an active lifestyle can significantly attenuate the
obesity risk for the same population (3, 4, 6). Along with the personalized pre-
cision-nutrition concept, the effects of phytochemicals, newly engineered
processed foods, specialized dietary supplements, and diet-microbiota interac-
tions represent some of the hot topics occupying nutrition science.
Precision nutrition integrates the primary factors that compose the person’s current
genotypic/phenotypic status (e.g. anthropometry, RMR, metabolic homeostasis, biochemical
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Primary factors that impact nutrition:
Geneticsand family
history
Diseaseor medicalconditions
DeficienciesCurrent
dailybehaviors
Activitystatus
Disorderedeating
patterns
Anthropometry Restingmetabolicrate
Metabolichomeostasis
Biochemicalinformation
Medicalconditions
CurrentdeficienciesCaloric
demands
Energysystemsused
Recovery
Demographics
Socioeconomiclevel
Dailybehaviors
PrecisionNutrition
DEFINITIONS
Nutrigenetics –
Study of the interaction between genetics and nutrient intake or dietary practices; seeks to elucidate optimal nutrient intake levels and strategies based on genetic variables.
Nutrigenomics –
Study of the means by which nutrients affect human genetic expressions, metabolic pathways and homeostatic control; seeks to elucidate how differences in dietary intake within ethnical or cultural subgroups have an impact on genetics over time.
Phytochemicals –
Specific active compounds found in plants shown to provide health benefits, but are not essential; not associated with a deficiency when lacking in the diet (e.g., lycopene in tomatoes).
information, medical conditions, current deficiencies, physical activity, caloric demands, energy
systems utilized, recovery) and secondary factors that affect nutrition with reference to general
nutritional guidelines (e.g. demographics, socioeconomic level, culture, food preference,
behavior) in order to provide comprehensive and dynamic nutrition optimization (1, 2).
Nutrition for Sports vs. Fitness All physical activities present a demand above resting homeostasis. Thus,
nutrition for sport must satisfy these energy demands of competition and
training without allowing premature fatigue. But the different aspects
of the activities humans engage in for pleasure and competition present an
assortment of considerations for nutritional support. Most physical activities
are classified as anaerobic or aerobic. From a sports-science perspective, this
concept is somewhat rudimentary, as all metabolism may be sourced during
a practice or competition; however, from a pragmatic perspective, this
model’s simplicity is easier to understand and helps manage nutritional fac-
tors. Anaerobic activities are high-powered, require exertional bursts and
rapid movement velocities, and include tennis, baseball, and hockey. On the
other hand, endurance-based activities are labeled aerobic, such as cross-
country running and triathlon training. Aerobic sports tend to require
sustained lower force outputs for longer durations but are often very
demanding at the competitive level. The nutritional needs of each player or
participant will be specific to the sport’s demands, participation frequency,
and input from all other stressors, including those of psycho-emotional
origin. This scenario suggests that nutritional planning must consider all aspects of being
human, not just the physical ones.
Training programs designed for athletes are based on specific sport analysis. Activities are
selected to align with the desired physiological adaptations and are applied in a planned
sequence by specific dosage. Similarly, the dietary strategy must comply with the athlete’s needs
in a manner specific to the physiological demands of his or her sport. This includes volume and
intensity, which will often vary by season. Identifying the actual demands of
a sport, along with the added challenges of practice and training, is the first
step in developing a nutritional plan for athletic performance.
While similarities exist, eating for fitness differs from eating for per-
formance because the former focuses more on isolated outcomes. Both diet
modes require nutrient specificity to support variations in activity type, inten-
sity, and duration while maintaining desirable levels of body fatness.
Nutrition for fitness emphasizes food intakes that optimize one or more com-
ponents of health-related fitness, often for physique competitions and
single-day events, such as a 10K or adventure race. A diet of this nature must
be well-planned, tends to be more restrictive, and is much more sensitive to
daily variations. On the other hand, athletes need nutrient and caloric density
for performance, so they can be less concerned with calorie counting or even
being visually lean. Athletes never want to run out of energy during a sporting
event, whereas fitness competitors go into contests with low energy provisions
on purpose as the goal is aesthetics. Eating for sports performance also differs
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Chapter 1 NCSF Sport Nutrition
Introduction to Sports Nutrition
Nutritional intake for sport must satisfy the energy demands of competition/training and thwart premature fatigue.
Eating for fitness and performance is quite different. Fitness competitors often focus on aesthetics while athletes must make sure they do not run out of energy and can properly recover.
from many fitness goals because of the ideal size and weight specifications associated with each
sport. Whereas fitness nutrition may be employed to add or maintain muscle, athletes may not
have that same desire, as more body weight equates to more work and greater energy demands
during competition.
Regardless of the population, individuals who routinely exert efforts above the adaptation
threshold require more calories than those that do not. Routinely participating in resistance
training and aerobic exercise requires additional levels of both EYN and NEYN beyond that
needed for basic health, and these levels are further increased for sports. The total number
of calories expended each day should be monitored and accounted for to ensure proper
recovery and the presence of suitable glycogen and water in the system for the next bout of
exercise or activity.
Goals of Sports Nutrition Historically, guidelines have suggested consuming a calorie-controlled diet, composed
primarily of a variety of fruits and vegetables, complex carbohydrates, and lean protein, while
limiting the consumption of unhealthy fats, processed carbohydrates, and simple sugars. These
guidelines form the basis of the recommended daily allowances (DRI-RDAs) as presented by
the United States Department of Agriculture and intend to cover the nutrient needs for more
than 90% of the population. And while sound in foundation, these recommendations lack the
specificity to account for those who routinely engage in higher levels of activity. Often,
nutritional adjustments must be made to manage the additional requirements of both EYN
and NEYN. Individuals who participate in fitness training will often burn 1,500 to 2,500
calories a week. Competitive athletes on the other hand, may burn more than 1,000 calories
in a single day.
The first goal depends heavily on carbohydrates to ensure adequate glycogen stores are
preserved in the muscle and liver, and to maintain an appropriate blood-glucose level. Addi-
tionally, healthy fats aid importantly in caloric balance. A key element to this goal is timing
nutrition around physical activity to fuel muscle and liver cells using hormonal advantages.
Fluid and electrolytes are also crucial to facilitate work and recovery demands during and
following activity.
The second goal depends more upon protein and minerals to ensure tissues have specific
nutrients in appropriate quantities to enable repair. Protein and minerals make up soft and hard
tissues and function in the process of catabolism and anabolism in response to external stim-
ulus and the internal environment. While food timing also aids in this goal, precise protein
content and specific nutrient-dense foods rich in calcium, phosphorus, and magnesium should
be included in the diet.
The final goal is rather encompassing, but speaks to the need to treat the body as a complete
organism, so all systems remain efficient. The body uses nutrients for simple to complex tasks
across the metabolic pathways. Amino acids derived from proteins play an important role in
metabolic function and support enzyme and hemoglobin formation. Proteins are further com-
plemented by NEYN, forming structures and serving roles in metabolic and regulatory
operations. This aspect of sports nutrition warrants dietary evaluation for nutrient balance and
sufficiency. Dietary support of the immune system is of key importance to this goal as it is a
primary contributor to recovery.
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Introduction to Sports Nutrition
To attenuate the stresses associated with training, sports nutrition strives to accomplish three primary goals:
• Providing adequate energy to
support work and recovery.
• Ensuring nutrient balance
supports cellular demands for
growth, maintenance, and repair.
• Providing adequate support for
efficient metabolic and immune
function.
DEFINITIONS
Catabolism –
Metabolic activity associated with the breakdown of tissues or energy reserves within the body.
Anabolism –
Metabolic activity associated with the building of tissues or storage of energy reserves within the body.
The Demands of Sport
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Introduction to Sports Nutrition
Table 1. Total Mean Nutritional Intake Among Male Athletes
Energy (Kcal)
Energy (MJ)
CHO (g)
PRO (g)
FAT (g)
Fluid (mL)
Fiber (g) CHO * PRO FAT
2994 ± 556 ★
12.6 ± 2.3 ★
390 ± 76 ★
117 ± 28 ★
96 ± 20 ★
2915 ± 788 ★
34 ± 7 ★
55.1 16.1 ◆
28.8Endurance (n = 157)
3784 ± 593
15.9 ± 2.5
489 ± 76
156 ± 31
119 ± 19
3628 ± 839
45 ± 6 54.8 17.4 27.8Rowing
(n = 34)
2275 ± 211
9.6 ± 0.9
303 ± 32
82 ± 8
76 ± 13
1805 ± 232
23 ± 2 56.0 14.7 29.3Soccer youth
(n = 63)
2700 ± 300
11.4 ± 1.3
361 ± 66
114 ± 13
83 ± 3
2692 ± 464
252 ± 2 55.1 17.3 27.6Soccer talent
(n = 26)
2841 ± 398
11.9 ± 1.7
341 ± 51
135 ± 13
95 ± 14
3550 ± 743
262 ± 5 50.2 19.4 30.4Soccer prof
(n = 30)
3055 ± 542
12.8 ± 2.3
373 ± 86
120 ± 20
104 ± 20
2825 ± 715
265 ± 8 52.5 16.9 30.7Water polo
(n = 12)
2566 ± 138
10.8 ± 0.6
274 ± 25
109 ± 10
105 ± 14
2102 ± 361
218 ± 1 46.0 17.0 37.0Hockey
(n = 7)
3076 ± 638
12.9 ± 2.7
413 ± 84
130 ± 16
92 ± 26
2624 ± 518
36 ± 7 56.2 17.2 26.6Swimming
(n = 11)
2904 ± 481
12.2 ± 2.0
381 ± 77
113 ± 21
98 ± 14
2480 ± 533
31 ± 3 54.2 15.8 30.0Ice skating
(n = 15)
2735 ± 444
11.5 ± 1.9
363 ± 55
111 ± 18
85 ± 18
2389 ± 733
31 ± 6 56.4 16.4 27.1Road cycling
(n = 34)
2946 ± 317
12.4 ± 1.3
419 ± 87
110 ± 11
82 ± 10
3160 ± 735
39 ± 9 59.3 15.4 25.3Running
(n = 8)
2681 ± 239
11.3 ± 1.0
337 ± 35
95 ± 11
90 ± 18
2941 ± 643
29 ± 3 54.6 15.0 30.4
Ultra endurance (n = 55)
2561 ± 395 ★
10.8 ± 1.7 ★
327 ± 56 ★
104 ± 21 ★■
85 ± 14 ★
2455 ± 791 ★
24 ± 4 ★■
53.8 16.5 29.7Team (n = 138)
3212 ± 225
13.5 ± 0.9
400 ± 21
150 ± 29
99 ± 9
2759 ± 398
32 ± 1 52.2 19.0 28.8Track cycling
(n = 5)
2739 ± 696
11.5 ± 2.9
383 ± 85
109 ± 27
76 ± 38
2599 ± 783
35 ± 10 59.4 16.0 24.6BMX
(n = 12)
2969 ± 127
12.5 ± 0.5
369 ± 15
132 ± 3
99 ± 12
3352 ± 110
35 ± 2 52.5 17.6 29.9Sprint/bobsled
(n = 4)
3308 ± 172
13.9 ± 0.7
300 ± 53
161 ± 12
144 ± 17
3314 ± 290
29 ± 5 40.6 19.8 39.6CrossFit
(n = 5)
2291 ± 288
9.6 ± 1.2
263 ± 59
111 ± 17
81 ± 3
2519 ± 556
25 ± 7 47.7 19.7 32.6Archery
(n = 6)
2846 ± 395
12.0 ± 1.7
348 ± 61
127 ± 24 ■
94 ± 28
2815 ± 475
32 ± 6 ■ 52.3 18.0
◆29.8Strength
(n = 32)
Absolute Mean Intake
Macronutrient Contribution for Total Energy (TE%)
Intake values are expressed as mean intake ± SD; Differences between categories are indicated by symbols (one-way ANOVA: p < 0.05, with post-hoc Bonferroni correction), each comparison between groups has its own symbol; ★ Endurance vs. Team, ◆ Endurance vs. Strength and ■ Team vs. Strength; No analysis was performed for testing differences between sports within the categories for endurance, team, and strength sports; * TE% for CHO includes estimated TE% of dietary fiber.
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Table 2. Total Mean Nutritional Intake Among Female Athletes
Energy (Kcal)
Energy (MJ)
CHO (g)
PRO (g)
FAT (g)
Fluid (mL)
Fiber (g) CHO * PRO FAT
2459 ± 520 ★◆
10.3 ± 2.2 ★◆
312 ± 58 ★◆
97 ± 19 ★
81 ± 28 ★
2842 ± 930 ★
32 ± 8 ★◆
54.2 16.4 ★◆
29.5Endurance (n = 83)
2909 ± 662
12.2 ± 2.8
362 ± 50
112 ± 23
99 ± 45
3228 ± 657
39 ± 10 54.2 16.1 29.7Rowing
(n = 26)
1965 ± 293
8.3 ± 1.2
256 ± 31
76 ± 4
66 ± 13
1695 ± 255
20 ± 5 54.2 15.8 30.0Soccer youth
(n = 16)
1998 ± 86
8.4 ± 0.4
260 ± 12
87 ± 5
59 ± 9
2585 ± 485
27 ± 3 55.6 17.8 26.6Volleyball
(n = 18)
1873 ± 111
7.9 ± 0.5
245 ± 29
75 ± 7
58 ± 12
2087 ± 389
24 ± 7 55.6 16.4 28.0Water polo
(n = 12)
2056 ± 207
8.6 ± 0.9
244 ± 44
93 ± 0
71 ± 10
2794 ± 594
23 ± 3 49.9 18.5 31.6Rugby Sevens
(n = 29)
2091 ± 373
8.8 ± 1.6
259 ± 37
89 ± 10
70 ± 20
2216 ± 562
26 ± 3 52.9 17.5 29.6Hockey
(n = 11)
1955 ± 224
8.2 ± 1.0
222 ± 21
92 ± 27
69 ± 3
2767 ± 617
24 ± 8 48.0 19.4 32.6Handball
(n = 18)
2495 ± 335
10.5 ± 1.4
341 ± 41
105 ± 13
70 ± 7
2429 ± 652
32 ± 3 56.8 17.2 26.0Swimming
(n = 9)
2224 ± 424
9.3 ± 1.8
283 ± 61
85 ± 11
78 ± 12
2209 ± 468
26 ± 3 53.2 15.8 31.0Ice skating
(n = 11)
2127 ± 363
8.9 ± 1.5
264 ± 53
92 ± 14
69 ± 13
3121 ± 1324
30 ± 9 53.1 17.9 29.0Road cycling
(n = 14)
2299 ± 102
9.7 ± 0.4
297 ± 25
96 ± 5
73 ± 10
2429 ± 977
30 ± 6 53.7 17.3 29.0Running
(n = 11)
2205 ± 288
9.3 ± 1.2
280 ± 61
76 ± 15
75 ± 12
2949 ± 1080
29 ± 8 54.6 14.3 31.1
Ultra endurance (n = 12)
1997 ± 201 ★
8.4 ± 0.9 ★
247 ± 32 ★
87 ± 10 ★
66 ± 11 ★
2441 ± 631 ★
24 ± 5 ★
52.2 17.8 ★
30.0Team (n = 104)
2202 ± 46
9.3 ± 0.2
285 ± 13
97 ± 18
67 ± 2
2385 ± 885
26 ± 4 54.0 17.9 28.1Track cycling/BMX
(n = 6)
2269 ± 401
9.5 ± 1.7
297 ± 58
88 ± 16
75 ± 19
2514 ± 778
24 ± 6 54.4 16.4 29.2Sprint/bobsled
(n = 8)
2609 ± 329
10.9 ± 1.4
240 ± 27
130 ± 37
108 ± 26
2834 ± 645
33 ± 9 41.2 20.3 38.5CrossFit
(n = 6)
2244 ± 296
9.4 ± 1.2
278 ± 58
101 ± 7
72 ± 5
3670 ± 788
30 ± 2 53.1 18.5 28.4Sailing
(n = 6)
1566 ± 92
6.6 ± 0.4
199 ± 29
72 ± 8
48 ± 6
1691 ± 136
20 ± 1 53.6 18.9 27.5Gymnastics
(n = 13)
2073 ± 417 ◆
8.7 ± 1.7 ◆
251 ± 46 ◆
92 ± 23
69 ± 21
2447 ± 866
25 ± 6 ◆ 51.8 18.4
◆29.8Strength
(n = 39)
Absolute Mean Intake
Macronutrient Contribution for Total Energy (TE%)
Intake values are expressed as mean intake ± SD. Differences between categories are indicated by symbols (one-way ANOVA: p < 0.05, with post-hoc Bonferroni correction), each comparison between groups has its own symbol, ★ Endurance vs. Team, ◆ Endurance vs. Strength and ■ Team vs. Strength. No analysis was performed for testing differences between sports within the categories for endurance, team, and strength sports * TE% for CHO includes estimated TE% of dietary fiber (13).
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Introduction to Sports Nutrition
Table 3. Energy Intake of Endurance Athletes in the Preparation and Competition Phases (5)
Preparation Competition
Endurance discipline n Energy intake [kcal/day] Energy intake [kcal/kg.day] n Energy intake [kcal/day] Energy intake [kcal/kg.day] Cyclists Total 46 3789 ± 765d,e,f 52.3 ± 13.3d,e 133 3600 ± 1102d 46.9 ± 17.7d,f Male 46 3789 ± 764d,e 52.3 ± 13.3d,e 125 3603 ± 1137 45.9 ± 18.0 Female – – – – – – Runners Total 278 2489 ±425a 38.2 ± 7.8a 272 3042 ±788 42.7 ± 4.7 Male 207 2640 ± 366a,b,f 38.3 ± 8.6a 203 3298 ± 713b 43.8 ± 3.2b Female 71 2046 ± 230a 38.0 ± 4.6c 69 2291 ± 443 39.4 ± 6.4 Swimmers Total 73 3366 ± 902a,d,e,g 48.7 ± 9.6a,d,e 55 2769 ± 681g,h 40.1 ± 7.7g Male 39 3963 ± 762a,b 53.2 ± 9.5a,b,d,e 24 3462 ± 341b 46.2 ± 6.5b Female 34 2683 ± 450a,d,e 43.6 ± 6.9a,e 31 2234 ± 256 35.4 ± 4.7 Rowers Total 70 2426 ± 448a 33.9 ± 4.5a 15 3633 ± 1097 46.8 ± 10.9 Male 24 2921 ± 326b,f 36.0 ± 0.1b – – – Female 46 2168 ± 330 32.8 ± 5.2c – – – Cross-country skiers Total 138 3224 ± 917a,d,e,g 48.3 ± 12.7a,d,e 33 2091 ± 53.2d,e,f,g 32.7 ± 2.9c Male 124 3287 ± 876d,f,g 48.3 ± 11.6d,e – – – Female 14 2663 ± 1107d,e 49.1 ± 20.3 – – – Triathletes Total 16 3162 ± 159d,e 45.7 ± 2.6e – – – Male 16 3162 ± 159d,e 45.7 ± 2.6e – – – Female – – – – – – Other endurance athletes Total 96 3261 ± 282a,d,e,g 46.5 ± 5.1a,d,e 14 4656 ± 1070 – Male 90 3274 ± 286a,d,f,g 46.3 ± 5.2a,d,e,f 14 4656 ± 1070c,d,f,g,h – Female – – – – – – Total Total 717 2915 ± 761a 42.8 ± 10.5 531 3156 ± 967 43.5 ± 11.3 Male 546 3111 ± 717a,b 44.0 ± 10.6b 407 3405 ± 940b 44.8 ± 11.9b Female 171 2291 ± 525 39.0 ± 9.1 124 2337 ± 483 39.3 ± 7.9 Note. Data are shown in weighted mean and standard deviation of the weighted mean (Xw ± SDw) n = cumulative number of subjects, – = insufficient data a Significantly different from athletes of the same endurance discipline and sex during competition phase (p<0.01) b Significantly different from females of the same endurance discipline and seasonal training phase (p<0.01) c Significantly different from all other endurance disciplines of the same sex and seasonal training phase (p<0.05) d Significantly different to runners of the same sex and seasonal training phase (p<0.05) e Significantly different to rowers of the same sex and seasonal training phase (p<0.05) f Significantly different to swimmers of the same sex and seasonal training phase (p<0.05) g Significantly different to cyclists of the same sex and seasonal training phase (p<0.05) h Significantly different to cross-country skiers of the same sex and seasonal training phase (p<0.05)
Specialized nutrition for sports or taxing physical activity implies that
athletes and fitness competitors must consume a diet that supports the meta-
bolic demands of training and competition while accounting for recovery.
Individual sports have been evaluated for specific nutritional require-
ments, and not surprisingly, research suggests that energy is the primary
predictor of success. Energy produces force, transfers and breaks down
nutrients, buffers nutrient byproducts, and regulates temperature. Not sur-
prisingly, the demand’s magnitude depends on the movement’s intensity and
duration.
Nutritional needs can be categorized by comparing different sports and
fitness activities. While no single diet is appropriate for all sports, nutrient
commonalities exist that can be categorically applied for appropriate recom-
mendations. Essentially, certain activities align nutritionally due to energy
system specificity and the similar caloric expenditure required at the compet-
itive level.
Historically, it has been thought that endurance athletes need more carbohydrates and
strength athletes more protein, but this is not necessarily accurate. Since endurance athletes
have a higher energy intake, they consume higher quantities of all nutrients, inclusive of carbo-
hydrates and protein. While protein is important for recovery, the idea that strength athletes
consume more protein than other athletes has not been confirmed. In fact, across a sample of
endurance, team, and strength-based sport athletes, consumption of energy-yielding nutrients
has a high level of consistency when expressed as percentage of the diet. That said, the current
consensus on carbohydrate and protein intake suggests that, while predictive, it is better not to
specify nutrient intake as a percentage of the total dietary energy intake. Rather, the need by
grams per kilogram of body weight (g·kg−1) should be determined to ensure relative require-
ments are being met. Part of the reason intake must be expressed in this manner is that the
current recommendations for energy intake demonstrate a considerable degree of variation.
The recommended intake range for carbohydrates and protein is rather broad, 3 to 12 g·kg−1 per
day for CHO and 1.2 to 2.0 g·kg−1 per day for protein, respectively. When expressed as a per-
centage, the information becomes specific to the quantity of calories and may or may not
address the needs of the body when adjusted for weight.
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NCSF Sport Nutrition Chapter 1
Introduction to Sports Nutrition
Research suggests the primary nutritional predictor for success in sport is energy. Energy is needed to produce force, transfer and break down nutrients, buffer nutrient byproducts, and regulate temperature.
Consider the following for a 70 kg male athlete: 70 kg x 1.5 g/kg = 105 g of protein per day = 420 kcal
15% of 2,400 kcal diet = 360 kcal
If this individual followed the RDA for protein, he would not meet his daily need of 1.5
g/kg/day. Individually breaking energy nutrients down by grams per weight and assigning
desirable endocrine-timing relationships should be of primary consideration for athletes and
physique competitors.
Additionally, these recommendations have a historical foundation, which may not be as
accurate today given the advancing understanding of training methods for high-level athletes.
Endurance and team-sports athletes for instance, also perform intense weight training. So, the
question now exists as to whether the significant differentiation in dietary intake between sport
disciplines is as appropriate as once thought given the multiple, overlapping stress demands.
Consider tables 1-3.
Each sport’s nuances provide the opportunity for fine-tuning via adjustments in energy-
nutrient recommendations, particularly for specific training and performance needs at different
times of the year. Additionally, males and females will demonstrate differences in nutritional
need particularly in total calories and specific micronutrients. That said, these differences are
not overly pronounced. When all sport athletes were compared, the mean estimated energy
intake, including nutritional supplements, for males was between 2,561 and 2,994 kcal per day,
whereas the mean energy intake for females ranged from 1,997 and 2,457 kcal per day. Not sur-
prisingly, the highest average intakes for males and females across all nutrients manifested in
the endurance sports categories. On the other hand, consider a systematic review of 48 studies
that analyzed the energy intake fluctuations of 717 highly trained endurance athletes across a
training season: it was found that relative energy intake during competition phases did not differ
from the preparation phase among either male or female endurance athletes (Table 3); however,
endurance athletes’ energy expenditure remained significantly higher than energy intake in both
preparation and competition phases (5). The same table also reflects the significant variations
in athletes’ energy consumption across different disciplines, even if all the events are classified
as endurance sports.
When dietary assessments are performed, most athletes seem to meet the requirements for
protein, based on minimum recommendations of 1.2 g·kg−1 but fail to ingest carbo hydrates at
the recommended level. This suggests one of two things: either the current recommendations
for carbohydrates are too high, or most athletes could benefit from additional carbohydrates in
their diet. The obvious premise behind elevated carbohydrate consumption is that sport-based
activities are performed at intensities that cannot be supported by the aerobic metabolism of
fats and proteins. This means carbohydrates serve as the primary fuel for energy metabolism
in sports. Even “aerobic” activities like distance running, cycling, and long-distance swimming
all use carbohydrates to fuel the faster speeds used at the competitive level. The need for protein
is well justified, but most dietary recommendations aimed at athletic performance attempt to
reach a proportion of 55-70% carbohydrates and 25-35% fat with protein only supplying
between 10-15% of calories. Interestingly, when successful athletes are analyzed, they all con-
sume more than 15% protein, with the exception of female ultra-endurance athletes. When
categorical activities are analyzed (e.g., endurance, team sports, strength) no group exceeds 60%
of calories from carbo hydrates. Certainly, endurance athletes consume the most carbohydrates,
but even their diets are at the bottom of the recommended range with a mean of 55%.
These findings seem to be consistent with non-elite athletes of varied endurance sports,
inclusive of winter triathlon (e.g., snowshoeing, skating, and cross-country skiing), winter pen-
tathlon (e.g., winter triathlon sports, cycling, and running), Ironman (IM: swimming, cycling,
12
Chapter 1 NCSF Sport Nutrition
Introduction to Sports Nutrition
running), and half-distance Ironman (IM 70.3). Nutritional analysis of these athletes identified
only 45.7% of all athletes reported consuming the recommended intake for carbohydrates, with
the highest proportion (66.7%) being those who competed in the half-ironman event. Equally
consistent with the elite athletes, the vast majority, (87.1%) reported consuming at least 1.2 g·kg-
1·day−1 of protein, and the majority of those who demonstrated sufficiency reported consuming
more than 1.6 g·kg−1·day−1. There was no difference in the proportion of athletes achieving the
recommended carbohydrate and protein intakes between men and women. These findings sug-
gest that among athletic populations, most do not meet the current recommendations for
carbohydrates, and many report total caloric intakes below more favorable estimates.
Energy though, is not the only limiting factor in human performance.
Athletes must not only fuel properly but should engage in training, practice, and
competition in a well-hydrated state to limit water and electrolyte deficits.
When an athlete is not properly hydrated, he or she loses extracellular fluid
stores and experiences shifts in electrolyte balance. This causes further detri-
ment to cellular function and a fairly linear decline in performance. To prevent
this problem, athletes must consume adequate energy in the form of carbo -
hydrates and manage fluid intake before, during, and after activity. Available
evidence suggests that many athletes enter physical activity with non-optimal
hydration levels and some experience some degree of dehydration even before
they start activity. Additionally, during training and practice, many fail to
drink enough to match sweat losses, whereas others drink too much, risking
hyponatremia. Athletes must learn a personalized hydration strategy balanced
with micronutrient intake that meets the needs of exercise, environmental
factors, and specific individual differences, as well as competition regulations.
Whereas nutrition before and during an event is relevant, recovery from activity requires
the most attention. Restoring liver and muscle glycogen stores is extremely important because
the metabolic opportunity to maximize stores has a limited window. Basic recommendations
have included consumption of up to 1.2 g⋅kg−1⋅h−1 of carbohydrate and 40 g of protein to aug-
ment protein synthesis. Consumption of appropriate nutrient sources should be prioritized
within 20-30 min following activity. Additionally, fluid and micronutrient needs should be
addressed within this time frame as well. A common recommendation is that 150% of body mass
lost during exercise should be consumed within 1 hour, with matched electrolytes. This measure
readies the body for recovery and for future muscle-tissue activity. An under-fueled and dehy-
drated athlete cannot compete optimally and experiences a much higher risk for injury. The
following text will review peak performance strategies across a broad range of activities.
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NCSF Sport Nutrition Chapter 1
Introduction to Sports Nutrition
Athletes are not only supposed to be properly fueled, but also need to engage training, practice, and competition in a well-hydrated state to limit water and electrolyte deficits.
DEFINITIONS
Hyponatremia –
A dangerous condition associated with abnormally low sodium levels in the blood (<135 mmol/L).
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Chapter 1 NCSF Sport Nutrition
Introduction to Sports Nutrition
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