CHAPTER 26 - Nutritional Guidelines and
Energy Needs for the Female Athlete-Determining
Energy and Nutritional Needs to Ameliorate
Functional Amenorrhea Caused by Energy
Imbalance
Jacalyn J. Robert-McComb, PhD
Fellow of the American College of Sports
Medicine
Learning Objectives
• Describe the energy availability hypothesis
and functional amenorrhea;
• Describe the energy and nutritional intake
estimations;
• Describe nutritional guidelines for the
female athlete; and
• Describe the importance of hydration
before, during, and after exercise.
Energy Drain and Menstrual
Dysfunction
• The prevalence of amenorrhea is elevated in
women who restrict their diets and are
intensely physically active (Torstveit &
Sundgot-Borgen, 2004).
• Warren was the first to suggest that
menstrual disorders in female athletes are
disrupted by an energy drain (Warren, 1980).
Disruption of Gonadotropin
Releasing Hormone (GnRH)
• Winterer et al. (1984) proposed the
hypothesis that failure to provide sufficient
metabolic fuels to meet the energy
requirements of the brain causes an
alteration in brain function that disrupts the
Gonadotropin releasing hormone (GnRH)
pulse mechanism.
Reproductive Function
• Reproductive function critically depends on
the pulsatile release of GnRH from GnRH
neurons in the arcuate nucleus of the
hypothalamus and on the consequent
pulsatile release of lutenizing hormone (LH)
from the pituitary (Loucks & Thuma, 2003).
Hypothalamus
GnRh
Pituitary
FSH LH
Ovaries
Estrogen Progesterone
Normal Menstrual Cycling
Follicular Phase
Luteal Phase
(around 14 days)
(around14 days)
Ovulation -LH Surge
(around day 14)
Suppression of LH
• In the athletic female, energy drain can occur by
either not taking in enough calories to meet the
metabolic needs of the body or by over exercising
and not compensating for the energy cost of the
exercise by taking in additional calories. Hence
LH pulsatility can be suppressed by a combination
of strenuous exercise and caloric restriction
(Loucks et al., 1998) if energy availability falls
below a critical threshold.
Functional Amenorrhea
• This has been termed "functional amenorrhea",
because the problem is a functional problem
(altered hormonal patterns), rather than an
anatomical problem (Loucks & Thuma, 1984).
The restoration of normal menstrual cycling has
been demonstrated to reoccur when the
individual's threshold for energy availability is
sequentially met (Locks & Callister, 1993).
Threshold of Energy Availability
• Loucks and Thuma (2003) found that LH
pulsatility was disrupted abruptly at a threshold of
energy availability not higher than 30 kcal/kg
LBM.d in regularly menstruating, habitually
sedentary young women of normal body
composition.
• They also found that the disruptive effects of sub
threshold energy availability were bimodal, with
substantially larger effects occurring in subjects
with the shortest luteal phases.
Loucks and Thuma (2003)
• Not all females have the same threshold for
energy- availability; but if this threshold
falls below a critical threshold, hormonal
alterations will result.
• The restoration of normal menstrual cycling
has been demonstrated to reoccur when the
individual's threshold for energy availability
is sequentially met.
Estimating Energy and Nutritional
Intake
• Studies consistently show that female athletes are
not consuming enough energy to support their
activity levels (Pate et al., 1990).
• Research with elite female swimmers, using the
doubly labeled water technique, noted that total
daily energy increased to 5, 593 kcal daily during
high-volume training.
• However their intake averaged only 3,136 kcal,
implying a negative energy balance (Trappe,
1997)
Estimated Calorie Requirements (in Kilocalories) for
Specific Age Groups at Three Levels of Physical Activitya
using the Institute of Medicine Equations
Activity
b,c,
Level
d
Gender
Age
(years)
Sedentary
b
Moderately
c
Active
Active
e
d
1,000 - 1,400
e
Child
2-3
1,000
1,000 - 1,400
Female
4-8
1,200
1,400 - 1,600
1,400 - 1,800
9-13
1,600
1,600 - 2,000
1,800 - 2,000
14-18
1,800
2,200
2,400
19-30
2,000
2,000 - 2,200
2,400
31-50
1,800
2,000
2,200
51+
1,600
1,800
2,000 - 2,200
Activity Levels
• Sedentary means a lifestyle that includes only the light
physical activity associated with typical day-to-day life.
• Moderately active means a lifestyle that includes
physical activity equivalent to walking about 1.5 to 3
miles per day at 3 to 4 miles per hour, in addition to the
light physical activity associated with typical day-today life.
• Active means a lifestyle that includes physical activity
equivalent to walking more than 3 miles per day at 3 to
4 miles per hour, in addition to the light physical
activity associated with typical day-to-day life.
Example of Specific Recommendations for Physically
Active Females from 19-30 years from the US Department
of Health and Human Services based on 2,400 calorie
pattern.
Food Group
Daily amount
Grains
Vegetables
8 ounces
3 cups
Fruits
2 cups
Milk
3 cups
Meat & Beans
6.5 ounces
Oils and Discretionary Calories
Aim for 7 teaspoons of oils a day
Recommendations for Macronutrients and
Energy Intake for the Physically Active Female
• The Food Guide Pyramid provides broad
recommendations for healthful nutrition for the
physically active individual.
• Diets should emphasize fruits and vegetables,
cereals and whole grains, nonfat and low-fat dairy
products, legumes, nuts, fish, poultry, and lean
meats.
• Female athlete’s diet have been found to be low on
iron, calcium, zinc, vitamin B6, and folate.
Continued
• Good sources of folate include fortified
breakfast cereal, soy flour, beans, wheat
germ, chicken and beef liver, papaya
(see http://www.swedish.org/15374.cfm)
• Studies consistently show that female athletes are
not consuming enough energy to support their
activity levels.
• Low energy and nutrient intake places athletes at
greater risk for nutrition related disorders such as
amenorrhea, osteoporosis, iron deficiency anemia,
and eating disorders.
Fat Intake
• Fat intake should not be restricted provided
that the fat intake is low in saturated fats
and trans fats;
• There is no benefit in consuming a diet with
less than 15% of energy from fat as
compared to 20-25%.
• Acceptable lipid intakes for physically
active individuals ranges from 20 and 35%
of caloric intake.
Carbohydrate Intake
• General recommendations for carbohydrates
range between 6-10g/ kg of body mass per
day.
• This range represents approximately 5565% carbohydrate intake.
• Carbohydrates should be predominantly
starches from fiber-rich, unprocessed grains,
fruits and vegetables.
Protein Requirements
• Protein requirements are slightly increased
in highly active people.
• Protein requirements for endurance athletes
are 1.2-1.4 g/kg body mass per day, whereas
those for resistance and strength trained
athletes may be as high as 1.6 to 1.7 g/kg of
body weight per day.
• According to the Dietary Reference Intakes,
acceptable macronutrient distribution ranges
of protein for adults are 10-35%.
The Importance of Hydration Before,
During, and after Exercise
• ACSM (1996) and NATA (Casa et al., 2000) recommend
drinking 400-600 mL (16 to 24 oz) of fluid 2-3 h before
the exercise.
• During exercise, optimal hydration can be facilitated by
drinking 150-350 mL (6 to 12 0z) of fluid at 15-20-min
intervals, beginning at the start of the exercise.
• Consuming up to 150% of the weight lost during an
exercise session may be necessary to cover loses in sweat
and urine excretion (Shirreffs et al. , 1996).
How Exercise Nutritionists Can Help
Female Athletes Maintain Energy Balance
• Athletes should be educated about energy
requirements for their sport and the role of food in
fueling the body.
• Female athletes should be educated about the
Female Athletic Triad and the long term health
consequences of inadequate energy intake.
• Unrealistic weight and body composition goals
should be discouraged.
• Body size and composition of an athlete
should be assessed for the determination of
an appropriate weight and composition for
the sports in which she participates.
• Minimum body composition for good health
for the female athlete is 12%.
• Provide the athlete with nutritionally sound
techniques for maintaining an appropriate
body weight and composition without the
use of severe diets or nutritionally
unbalanced macronutrient choices.