Nutrition for Athletics
Presented by
Janice Hermann, PhD, RD/LD
OCES Adult and Older Adult Nutrition Specialist
Nutrition for Athletics
 Being physically active has many health
benefits, and good nutrition plays an
important role in athletic performance.
 While the USDA Daily Food Plan provides the
foundation for a healthy diet, there are some
special dietary considerations for athletics.
Nutrition for Athletics
 Nutrition can affect body weight, body
composition and athletic performance.
 As interest in nutrition for athletic
performance has increased so have
promotions for ergogenic aids, supplements
and herbal products claiming to improve
athletic performance.
Calories
 Meeting calorie needs is a priority for athletic
performance.
 Inadequate calories can hinder athletic
training and performance. Inadequate
calories can result in loss of muscle as well as
body fat.
 Muscle loss can result in loss of strength and
endurance. In addition, inadequate calories
can result in poor nutrient intake.
Calories
 Calorie needs are affected by an individual’s
age, gender, body size, muscle mass, as well
as the frequency, intensity and duration of
physical activity.
 One way to determine if adequate calories
are consumed is if body weight and
composition are maintained.
Weight Change
 Athletes often want to increase or decrease
their body weight to meet sports demands.
 Weight change should occur slowly during the
off-season, or beginning of the beginning
before composition begins.
Weight Change
 Weight gain can be accomplished by an
increase in calorie intake by 500 to 1,000
calories per day in combination with an
increase in strength training which can result
in an increase in muscle mass.
Weight Change
 Weight loss can be accomplished by
decreasing calorie intake by 500 calories per
day while maintaining a healthy diet.
 Weight loss should be gradual, approximately
1-2 pounds/week.
 Slow weight loss contributes to a loss in body
fat while maintaining muscle. Rapid weight
loss increases the risk of losing muscle and
regaining weight.
Weight Change
 The best combination for weight loss is a
regular fitness program along with a wellbalanced, low-fat diet following the USDA
Daily Food Plan.
Weight Change
 Weight loss may seem small at first when
using a combination of diet and increased
physical activity, because muscle mass
increases at the same time body fat
decreases.
 However, greater weight loss becomes
apparent as body fat loss continues and
muscle gain levels off.
Weight Change
 Weight loss techniques involving loss of body
water are dangerous.
 Water loss results in decreased blood volume
and reduced blood flow to the kidneys, skin,
and muscles.
 This hinders the body’s ability to sweat and
regulate body temperature, and increases the
risk of dehydration.
Weight Change
 Determining a healthy body weight is critical.
 A healthy weight is one that can be
realistically maintained, allows for positive
increases in athletic performance and
minimizes risk of injury.
Weight Change
 Pressure to achieve unrealistic body weights
can lead to chronic dieting and eating
disorders in severe cases.
 In addition, pressure to loss weight can
encourage athletes to follow unhealthy
weight loss methods.
Weight Change
 Excessive weight loss can especially be a
problem for female athletes.
 In females, low calorie intakes in combination
with high energy expenditures can lead to
amenorrhea and loss of or failure to gain
bone mass.
Body Composition
 Body weight and composition are two major
factors that affect athletic performance.
 Body weight can affect speed, endurance, and
power; whereas body composition can
influence strength, agility and appearance.
Body Composition
 Most athletes need a high strength-to-weight
ratio to enhance athletic performance.
 Because body fat adds to weight without
adding strength, a low percentage of body fat
is often emphasized; however, too little body
fat can also hinder performance and health.
Body Composition
 Optimal body weight and composition differs
based on an age, gender, genetics, and type
of athletic event.
 Yet some athletic events set weight criteria
that may not be optimal for an individual
athlete – such as wrestling which may require
athletes to lose or gain weight for specific
weight categories.
Body Composition
 Other athletic events such as dance and
gymnastics may pressure athletes to lose
weight and have low body fat to have a lean
physique that may not be ideal.
 Extreme calorie restrictions can result in a
decreased in both body fat and muscle which
can hinder athletic performance.
Body Composition
 Optimal body fat percentages vary depending
on gender and the type of athletic event.
 Athletes who try achieve unrealistic
inappropriate body weight or body fat levels
may be at risk for eating disorders or other
health problems related to inadequate
calories or nutrients.
Macronutrients
 There isn’t evidence that athletes need a diet
significantly different from that
recommended in the Acceptable
Macronutrient Distribution Ranges:
 45-65% carbohydrate
 10-35% protein
 20-35% fat
Protein
 Protein needs for athletes have received a lot
of investigation, not only in terms of whether
protein needs are increased, but also in terms
of whether individual amino acids are
beneficial.
 Athletes do have slightly higher protein
requirements to support increased muscle
mass and muscle repair.
Protein
 The amount of increase depends on the type
of athletic activity, intensity, duration, and
possibly the gender.
 Protein requirement may vary from 1.2 g/kg
for endurance athletes to 1.7 g/kg for
bodybuilders and strength athletes.
 General adult RDA for protein 0.8 g/kg
 Increased protein beyond recommended
levels is unlikely to result in additional
increases in muscle mass.
Protein
 It is important to realize that if calorie intake
is not adequate, protein will be used for
energy.
 It is also important to realize that most typical
diets provide enough protein to cover even
the increased protein needs of athletes.
Protein
 The effect of using individual amino acids to
improve athletic performance has been
inconsistent.
 Because the safety and efficacy of individual
amino acid mixtures has not been
established, their use cannot be
recommended.
Vitamins and Minerals
 Vitamins and minerals have important roles in
athletic performance for energy production,
hemoglobin synthesis, bone health, immune
function, and protecting body tissues from
oxidative damage.
 Vitamins and minerals are also required to
help build and repair muscle.
Vitamins and Minerals
 Although theoretically, physical activity may
increase or alter vitamin and mineral
requirements; it is assumed that the current
Dietary Reference Intakes (DRIs) are
appropriate for athletes unless otherwise
stated.
Vitamins and Minerals
 Athletes at risk for poor vitamin and mineral
intakes are those who severely limit calories,
eliminate one or more of the food groups
from their diet, or consume highcarbohydrate, low nutrient dense diets.
Vitamins and Minerals
 Athletes participating in the previous types of
behaviors may need to use a
multivitamin/mineral supplement to improve
their overall nutritional status.
 Supplementing single vitamins and minerals is
discouraged unless there is a clear medical or
nutritional reasons; such as an iron
supplement for iron deficiency anemia.
Vitamins and Minerals
 The B-complex vitamins; thiamin, riboflavin,
niacin, vitamin B-6, pantothenic acid and
biotin are involved in energy production and
folate and vitamin B-12 are needed for the
production or red blood cells, protein
synthesis and tissue maintenance and repair.
Vitamins and Minerals
 There is limited research available to
determine if athletes need more B-complex
vitamins; however, the some research
suggests athlete may have a slightly higher
need for these vitamins, perhaps up to twice
the recommended amount.
 However, these increased needs can generally
be met by athletes higher calorie needs to
maintain body weight.
Antioxidant Nutrients
 Antioxidant nutrients such as vitamins A, E,
and C, beta-carotene, and selenium have
important roles in protecting cell membranes
from oxidative damage.
 Because physical activity increases oxygen use
it has been hypothesized that intense physical
activity produces “oxidative stress.”
Antioxidant Nutrients
 Thus, at this time there is no clear consensus
on whether athletes need additional
antioxidant nutrients.
 Athletes at greatest risk for poor antioxidant
status are those who limit calories, consume a
low-fat diet, or limit fruit and vegetable
intake.
Minerals
 Minerals typically low in athletes diets,
especially for females, include calcium, iron
and zinc.
 Low intake of these minerals is usually due to
low calorie intake or limiting animal products
such as meat, fish, poultry, and dairy
products.
Calcium
 Calcium is important for building and
repairing bone and maintaining blood calcium
levels.
 Inadequate calcium intake increases the risk
of low bone mineral density and stress
fractures.
 Female athletes are at greatest risk for low
bone mineral density if calorie intake is low,
dairy products are omitted from the diet, and
amenorrhea is present.
Vitamin D
 Vitamin D is needed for calcium absorption,
regulation of blood calcium levels, and bone
health.
 Two main sources of vitamin D are fortified
foods, such as milk, and production of vitamin
D by sunlight exposure on the skin.
Vitamin D
 Athletes living in northern regions, who train
and compete indoors throughout the year
such as gymnasts and figure skaters are at
greater risk for poor vitamin D status if they do
not consume foods fortified with vitamin D.
 These athletes may benefit from vitamin D
supplementation at the recommended DRI
level.
Iron
 Iron has an important role in the formation of
hemoglobin and myoglobin, which carry
oxygen in the body, and for enzymes involved
in energy production.
 Iron depletion is a common nutrient problem
among athletes, especially females.
Iron
 If iron depletion progresses to iron deficiency
anemia, athletic performance can be
hindered.
 Iron depletion is usually due to low calorie
intake, limiting meat, fish and poultry that
contain iron in the readily available heme
form, vegetarian diets that contain foods with
low iron bioavailability, or increased iron
losses.
Iron
 Female athletes and long-distance runners
should be periodically screened to evaluate
their iron status.
 Because iron deficiency anemia can take
three to six months to reverse early
nutritional intervention is beneficial.
Iron
 Some athletes may develop a transient
decrease in hemoglobin when they begin
training as a result of the increase in blood
volume which dilutes hemoglobin.
 This situation doesn’t appear to hinder
athletic performance.
Zinc
 Most dietary zinc comes from animal foods
and a majority of people consume less than
DRI amounts recommended.
 Because zinc has important roles in growth,
building and repairing muscle tissue, and
energy production, it is prudent to evaluate
zinc status, especially among female athletes.
Fluids
 It is well known that dehydrate can hinder
athletic performance.
 In addition, dehydration can increase the risk
of heat stroke which is potentially lifethreatening.
 Thus athletes need to keep well-hydrated
before and during physical activity.
Fluids
 One way the body cools itself by vaporizing
water.
 Sweat rates vary depending of body size,
exercise intensity, temperature, humidity and
acclimation but can exceed 1,800 mL/hour.
 In addition, to water, sweat contains
substantial amounts of sodium and modest
amounts of potassium.
Fluids
 Fluid balance is maintained if fluid intake and
absorption equals fluid loss through sweating,
and in longer events – urination.
 Fluid balance during physical activity is not
always possible because maximum sweat
rates exceed maximum stomach emptying,
which limits fluid absorption.
Fluids
 However, usually athlete’s fluid intake during
physical activity is less that the amount that
can be emptied from the stomach and
absorbed.
 Athletes often consume less than 500
mL/hour during competition and the stomach
emptying rate is more than 1 L/hour.
Fluids
 Stomach emptying is increased when the
amount of fluid in the stomach is high.
 Stomach emptying is decreased with
concentrated fluids, carbohydrate
concentration is greater than or equal to 8%.
Fluids
 Dehydration, hypohydration, and
hyponatremia are all distortions in fluid and
electrolyte balance that can be lifethreatening.
 Dehydration can occur when fluid losses
exceed fluid intakes.
 Hypohydration can occur when athletes
dehydrate themselves before beginning an
event – such as to make a weight category.
Fluids
 Hyponatremia (low blood sodium
concentrations) can occur due to prolonged,
heavy sweating without replacing sodium, or
when excess water is retained in the body.
 Although endurance athletes are more likely
to suffer from dehydration than from
hyponatremia (overhydration), hyponatremia
is not uncommon.
Fluid and Electrolyte Recommendations
 Before Activity: Athletes should be well-
hydrated before physical activity.
 Recommendations are to drink generous
amounts of fluid 24 hours before an event,
and 400 to 600 mL of fluid 2-3 hours before
an event (1.5-2.5 cups).
 This amount should maximize hydration while
still allowing enough time for excess fluid to
be excreted in the urine.
Fluid and Electrolyte Recommendations
 During Activity: During an event athletes
should try to drink enough fluid to maintain
fluid balance.
 Even partial dehydration can hinder athletic
performance.
Fluid and Electrolyte Recommendations
 During Activity: If fluid balance cannot be
maintained, the maximal amount of fluid that
can be tolerated should be consumed.
 Athletes can optimize hydration by drinking
150 to 350 mL of fluid (approximately 6-12 oz)
every 15 to 20 minutes during the event.
Fluid and Electrolyte Recommendations
 Beverages contain carbohydrate at
concentrations of 4-8% are recommended for
events lasting longer than one hour.
 These types of beverages are also acceptable
for hydration during events lasting less than
one hour although plain water is also
appropriate under these conditions.
Fluid and Electrolyte Recommendations
 Little need to replace electrolytes for events,
less than 3 to 4 hours, especially if pervious
meal contained sodium.
 However, consuming beverages containing
modest amounts of sodium is recommended
during events lasting longer than one hour
because it may increase acceptability and
desire to drink, thus increasing the amount of
fluid consumed.
Fluid and Electrolyte Recommendations
 Consuming beverages containing sodium may
also help prevent hyponatremia in susceptible
people.
 Although most athletes who consume more
fluid than they lose in sweat excrete the
excess fluid as urine, some people retained
fluid.
Fluid and Electrolyte Recommendations
 Beverages containing sodium could help
prevent dilution of blood sodium levels, thus
decreasing the risk of hyponatremia.
 Limiting fluid intake so that it does not exceed
losses from sweat can also decrease the risk
of hyponatremia.
Fluid and Electrolyte Recommendations
 After Activity: Usually athletes do not consume
enough fluids during activity to balance fluid
losses.
 As a result most athletes are dehydrated to some
extent at the end of athletic events.
 Consuming up to 150% of weight lost during an
activity may be needed to replace losses in
sweat and urine. Including sodium in fluids
reduces diuresis that occurs with plain water.
Fluid and Electrolyte Recommendations
 After Activity: Sodium also helps the body
rehydrate by maintaining blood osmolality
and thus the desire to drink.
 Because most commercial beverages do not
contain enough sodium to maximize post
activity fluid replacement, sodium containing
beverages should be consumed in
combination with a sodium containing meal.
Weather Conditions
 Hot and humid weather: The risk of
dehydration and heat related injury increases
dramatically in hot and humid weather.
 If outside temperature exceeds body
temperature, heat cannot be released by
radiation.
 If humidity is high, the ability to remove heat
by sweat evaporation decreases.
Weather Conditions
 Hot and humid weather: If both temperature
and humidity are high, there is a very high risk
of heat related illness and athletic events
should be delayed.
 If athletic activities do occur under these
conditions, precaution should be taken to be
sure that athletes consume plenty of fluids
and are monitored for heat related illness.
Weather Conditions
 Cold weather: Although the risk of
dehydration is greater in hot weather,
dehydration is not uncommon in cold
weather.
 Factors can contribute to dehydration in cold
temperatures include respiratory fluid losses
in cold dry temperatures, as well as sweat
losses that may be high if insulated clothing is
worn during intense athletic events.
Weather Conditions
 Cold weather: Dehydration can also occur
due to low fluid intake.
 Low fluid intakes can occur if an athlete is
cold and available fluids are cold, which can
reduce the athlete’s desire to drink.
 In addition, difficulty removing multiple layers
of clothing to urinate may cause some
athletes to voluntarily limit fluid intake.
Weather Conditions
 Altitude: Altitudes higher than 8,200 feet may
result in fluid losses beyond those due to
physical activity.
 These losses occur due to mandatory diuresis,
high respiratory water losses, and decreased
appetite.
Weather Conditions
 Altitude: Under circumstances of weight
maintenance, diuresis in about 500 mL/day
and lasts for about 7 days.
 Respiratory water losses may be as high as
1,900 mL/day in men and 850 mL/day in
women.
 Thus, fluid intake should be increased at high
altitude to as much as 3 to 4 L per day to
assure optimal kidney function.
Training Diet
 Portion of calories from protein, fat, and
carbohydrate for athlete’s training diets don’t
differ substantively from current
recommendations for the general population.
 Thus athlete’s training diet should follow the
guidelines recommended by the Dietary
Guidelines for Americans and the USDA Daily
Food Plan.
Training Diet
 The main differences between an athlete’s
diet and that of the general population are
that athletes need additional fluid to cover
sweat losses and calories to for the physical
activity itself.
 Much of additional calorie needs should be
supplied by carbohydrate.
Training Diet
 Although in some cases the need for other
nutrients may also increase (protein, Bcomplex vitamins), the increase in calorie
needs appear to exceed the increased need
for other nutrients.
 As a result, as calorie needs increase, athletes
should first try to consume the recommended
amount of foods from the USDA Daily Food
Plan food groups.
Training Diet
 Another issue for athletes is the timing of
meals and snacks.
 For the most part foods and fluids consumed
around athletic activities need to be
determined on an individual basis and will
partly depend on an athlete’s gastrointestinal
characteristics and activity intensity.
Training Diet
 An individual may be able to handle a snack
of milk and a sandwich one hour before a
light activity, but would be uncomfortable if
the same snack was consumed before a very
hard activity.
 Athletes in heavy training or participating in
multiple daily workouts may need to eat more
than 3 meals and 3 snacks per day.
Pre Activity Meal
 Eating before physical activity has been
shown to improve athletic performance
versus being in a fasting state.
 A meal or snack before and event or an
intense workout should prepare the athlete
for the event, not leave them hungry or with
undigested food in their stomach.
Pre Activity Meal
 Recommendations for meals and snacks
before events are that they should provide
enough fluid to maintain hydration, be low in
fat and fiber to help gastric emptying and
lower gastrointestinal distress, be high in
carbohydrate to maintain blood glucose and
maximize glycogen stores, be moderate in
protein, and contain foods the athlete is
familiar with.
Pre Activity Meal
 The size and timing of pre-competition meals
are interrelated.
 Because most athletes do not like to compete
on a full stomach, smaller meals should be
consumed closer to the time of the event to
allow for gastric emptying, whereas larger
meals can be consumed if adequate time is
available before competition.
Pre Activity Meal
 The amount of carbohydrate consumed in
studies in which athletic performance is
enhance range from approximately 200 to
300 g carbohydrate for meals consumed 3 to
4 hours before the competition.
Pre Activity Meal
 Recommendations on the amount of
carbohydrate consumed within one hour
before an event is controversial.
 Early research suggested this could lead to
hypoglycemia and premature fatigue;
however, more recent studies have reported
either no effect or beneficial effects of preevent carbohydrate intake on performance.
Pre Activity Meal
 The form of pre-competition meals and
snacks depends on athlete’s individual
tolerances.
 Some athletes can handle regular meals 2 to 4
hours before exercise; however, this may
cause severe gastrointestinal distress for
others and they may do better with liquid
meals.
During Activity
 Consuming carbohydrate in amounts typically
supplied in sports drinks (4-8%) improves
performance in events lasting one hour or
less has been controversial.
 Current research now supports the benefit of
this practice, especially in athletes who are
physically active in the morning after an
overnight fast when liver glycogen levels are
low.
During Activity
 For longer events, consuming 0.7 g
carbohydrate/kg body weight per hour
(approximately 30 to 60 g carbohydrate per
hour) has been shown to extend endurance
performance.
 Consuming carbohydrate during physical
activity is even more important for athletes
who have not carbohydrate-loaded,
consumed a pre-event meal, or restrict calorie
intake for weight loss.
During Activity
 Carbohydrate intake should begin shortly
after the onset of physical activity.
 Research has shown that consuming a larger
amount of carbohydrate after 2 hours of
physical activity is not as effective as
consuming the same amount of carbohydrate
in 15 to 20 minute intervals during the first 2
hours of physical activity.
During Activity
 The type of carbohydrate should provide
primarily glucose; fructose alone is not as
effective and may lead to diarrhea, although
mixtures of glucose and fructose seem to be
effective.
 The form of carbohydrate, solid food or liquid
doesn’t seem to matter and is more a matter
of personal preference.
Post Activity Meal
 Timing and composition of the post activity
meal or snack depends on the length and
intensity of the physical activity (whether
glycogen stores are depleted) and when the
next intense physical activity will occur.
Post Activity Meal
 After a marathon most athletes will have
depleted glycogen stores; whereas after a 60
minute training session, glycogen stores may
not be depleted.
 However, most athletes after completing a
marathon won’t be competing in another
marathon the next day.
Post Activity Meal
 As a result, the timing and composition of
post activity meals for these athletes is less
important because they have time to restore
glycogen store.
 However, post event recovery is very
important for athletes who participate in
multiple events in one day or have a short
recovery time between events.
Post Activity Meal
 Timing of post activity carbohydrate affects
glycogen stores. Carbohydrate consumed
immediately after physical activity (1.5 g
carbohydrate/kg at 2 hour intervals) results in
higher glycogen stores than if carbohydrate
intake is delaying for 2 hours.
 Timing of post activity carbohydrate is not as
critical for athletes who have one or more
days between intense events.
Post Activity Meal
 If adequate carbohydrate is consumed over a
24 hour period, the timing of carbohydrate
intake does not appear to affect the amount
of glycogen stored.
 However, consuming a meal or snack close to
the end of physical activity may be important
for athletes to meet their carbohydrate and
calorie needs.
Post Activity Meal
 The type of carbohydrate consumed can also
affect post exercise glycogen stores.
 In regards to simple sugars, glucose and
sucrose are equally affective if consumed at a
rate of 1.5 g/kg body weight for 2 hours;
however, fructose alone is less effective.
Post Activity Meal
 In regards to whole foods, consuming foods
with a high glycemic index produces higher
muscle glycogen stores 24 hours after activity
as compared to the same amount of
carbohydrate from foods with a lower
glycemic index.
 However, the usefulness of these findings
must be considered in terms of the overall
diet.
Post Activity Meal
 When similar amounts of carbohydrates or
carbohydrates, protein and fat are provided
following activity, glycogen synthesis is similar.
 Although including protein doesn’t appear to
enhance glycogen stores, including protein in a
post activity meal may provide needed amino
acids for muscle protein repair.
Ergogenic Aids
 Marketing of ergogenic aids (items claiming to
increase athletic performance) preys on
athletes.
 The 1994 Dietary Supplement Health and
Education Act allows supplement
manufactures to make claims regarding the
effect of products on the structure/function
of the body.
Ergogenic Aids
 Ergogenic aids must be carefully evaluated in
terns of the validity of the claim relative to
the science of nutrition, athletic performance
and health consequences.
Ergogenic Aids
 In general, most ergogenic aids fall into one of
the following categories:
 those that perform as claimed
 those that may perform as claimed but for which
there is insufficient evidence of efficacy at this
time
 those that do not perform as claimed
 those which are dangerous, banned, or illegal, and
should not be used.
Ergogenic Aids
 Use of ergogenic aids is controversial.
 Some health care professionals discourage
use of all ergogenic aids whereas others
suggest they be used with caution but only
after athletes have carefully evaluated of the
product for safety, efficacy, potency and
legality and discussed the use of the product
with a qualified nutrition or health
professional.