CHAPTER 14 • NUTRITION 85- High quality protein intake for the male endurance
athlete performing at intensities above 65–85% of
VO2peakshould be 1.0–1.6 g/kg body weight per day
or 150–175% of the current recommended dietary
allowances (RDA) for protein. This protein intake is
required to provide for the oxidation of amino acids
during high intensity exercise (Snyder and Naik,
1998). For example, a 150-lb man would need about
75 to 113 g of protein per day. Female athletes may
require 10–20% less protein than male athletes. - There does not appear to be an increased protein
requirement for individuals engaged in moderate-
intensity endurance exercise or <50% VO2peak
(Butterfield and Calloway, 1984). - Protein intake for strength athletes must be provided
to enhance muscle hypertrophy but must also be indi-
vidualized to the duration, frequency, and intensity of
the activity. In early stages of resistance training, the
estimated protein requirement is 1.5–1.7g/kg body
weight per day, but when training enters the mainte-
nance phase, the protein requirement decreases to
1.0–1.2 g/kg body weight per day (Lemon and
Tarnopolsky, 1992; Tarnopolsky et al, 1992). - Protein intakes above 2.0 g/kg body weight per day
are probably oxidized for energy and thus do not
enhance muscle mass or performance. - In general, animal proteins are higher quality proteins
than plant proteins. Animal proteins are complete pro-
teins providing all the essential amino acids in
amounts necessary for production of body proteins.
Plant proteins are incomplete and are not digested as
completely as animal proteins. Furthermore, animal
foods generally provide more protein per serving than
plant foods. Good sources of animal protein include
meat, eggs, and dairy products. Plant proteins include
grains, legumes, and vegetables. Soy protein is a plant
protein; however, soy protein is a higher quality pro-
tein than other plant proteins (Jeejeebhoy, 2000).
FATS
•Dietary fat intake should provide no more than 30%
of total kilocalories. For example, a 150-lb athlete
who consumes 3750 kcals a day would need 125 g of
fat. Endurance athletes in training may decrease their
intake to 20–25% of total kilocalories to enable them
to consume the larger quantities of carbohydrate
required to prevent staleness (Houtkooper, 1992;
Coleman, 1998).
- Adaptation to a high-fat diet (>60% kcals from fat)
will increase the contribution of fatty acid oxidation
by 40% to total energy expenditure of exercise; how-
ever, neither the rate of use of glycogen nor an
increased performance during moderate intensity
exercise has been observed (Helge et al, 1996).CARBOHYDRATES- The general guidelines for the endurance athlete are
that between 60 and 70% of total kilocalories, or 8 and
10 g/kg body weight should be in the form of carbo-
hydrates, especially for those participating in training
or events lasting longer than 1 h (Houtkooper, 1992;
Coleman, 1998; Joint position statement: Nutrition
and athletic performance, 2000).
•A 150-lb individual who requires 3750 kcals per day
of which 1920 to 2700 kcals should be carbohydrate
will need 480–675 g carbohydrate/day. - Endurance athletes training for less than 1 h a day can
resynthesize glycogen adequately on dietary intakes
of 6 g/kg body weight (Walberg-Rankin, 1995).
WATER/FLUID- In any event lasting longer than 30 min, fluid and
nutrient needs take on greater importance and can
influence performance.
•Water is the most important nutrient for regulating
hydration status in individuals.
•Water loss during exercise occurs primarily through
sweat. Sweat rate is influenced by ambient tempera-
ture, humidity, exercise intensity, and rate of exoge-
nous fluid intake. Water loss occurs in both the intra-
and extracellular fluid compartments, which can lead
to changes in electrolyte balance of both sodium and
potassium, particularly, and may influence cardio res-
piratory function. - The average person does not consume enough fluid to
offset sweat losses during exercise. Average losses
during exercise can amount to 2–6% of a person’s
body weight. Physical performance is impaired when
3–4% body weight is lost (Noakes, 1993).
•Physiologic changes accompanying dehydration
include impaired heat dissipation, decreased plasma
volume, and impaired skin blood flow, which can lead
to decreased stroke volume, increased heart rate, car-
diac drift, and ultimately heat stroke (Montain and
Coyle, 1992). - Fluid intake prior to exercise is necessary to offset risk
of dehydration during exercise. Drinking throughout
the day can ensure a euhydrated state. Consumption
of 400 to 600 mL of fluid 2 h prior to competition is
recommended (Latzka and Montain, 1999). - Fluid intake during exercise is necessary to replace
fluid lost through sweat at an equivalent rate. The
practical recommendation is to consume 150 to 350 mL