If perchance the athlete consumed a total of
10.9 MJ · day-^1 (2600 kcal · day-^1 ) (Steen et al.
1995), only 840 kJ (200 kcal) would remain for
protein and fat needs. This yields an impossible
task not only in providing adequate levels of
protein and fat, but in a practical sense as well.
Another CHO recommendation comes in the
form of total amount of CHO per day. The cur-
rently used 500–600 g CHO · day–1recommenda-
tion was derived from four trained male runners
whose average weight was 80 kg (Costill et al.
1981). As illustrated and reflected in current
intakes of females, these higher recommended
levels of CHO are not practical for the typically
lower weight female athlete.
Protein recommendations
When compared with CHO and fat, protein is a
nutrient with greater biological diversity in the
body, greater methodological challenges in its
study and with corresponding controversy in the
findings. The reader can find in-depth reviews
of amino acid metabolism in Chapter 9 and of
protein requirements in Chapter 10.
Recognized as important for the athlete,
protein is an energy nutrient that has a dietary
guideline of about 0.75 g · kg–1 ·day–1in the UK
(Department of Health 1991) and US (National
Research Council 1989). As previously men-
tioned, these recommendations are not set with
consideration for the effects of physical activity
or climate. Rationale for using the recommended
level of protein for both sexes stems from limited
evidence found during a nitrogen balance study
of six young women that requirement values,
when expressed per kilogram of body weight,
are not substantially different from those for
young adult men. Calloway and Kurzer (1982)
also noted in their study the importance of hor-
monal influences on the gain and loss of nitrogen
and cautioned others that failure to consider the
10 60 600
16 7
10
g CHO kg BW kg BW g CHO
kJ or g CHO
MJ or¥=
¥ ()
= (). 4 kcal
2400 kcal
effect of the menstrual cycle could lead to inaccu-
rate estimates of nitrogen/protein requirements.
Endurance athletes have greater protein
requirements than those of sedentary persons
(Tarnopolsky et al.1988; Meredith et al.1989).
Phillipset al.(1993) considered protein needs for
individuals engaged in habitual physical exer-
cise and concluded that 0.86 g · kg–1 ·day–1was
inadequate for endurance athletes. Females in
the study were eumenorrhoeic, not taking oral
contraceptives and matched to training levels of
males with the use of training and performance
histories. Male athletes exhibited higher absolute
leucine oxidation than females, yet an increase in
oxidation with exercise was proportionally
greater in the females. This was not explained
by the authors. In respect to methodology, a(^15) N-glycine isotope revealed a higher protein
turnover in elderly women (n=6) after they con-
sumed 20% of their total energy as protein than
after a 10% protein diet and no difference was
observed when a [1-^13 C] leucine method was
used (Pannemans et al.1997). Care must there-
fore be taken in choosing the stable isotope tracer
to measure protein turnover. The age of these
subjects and small sample size limit the applica-
tion of this research to female athletes, yet may
pose questions for researchers who investigate
protein utilizing leucine as a tracer.
While investigations of the most appropriate
isotope tracer may redirect protein research, the
more traditional nitrogen balance studies still
support increased protein needs for active indi-
viduals. Without support for a specific protein
requirement for the female athlete, reliance on a
thorough dietary assessment of protein quality
and energy intake followed with the provision
of current recommendations for protein is sug-
gested. Lemon (1995) suggests that endurance
athletes consume protein levels of 1.2–1.4 g · kg–1·
day–1and increased amounts for the strength
athlete, 1.4–1.8 g protein · kg–1· day–1. Unfortu-
nately, these recommendations are based on data
derived from male subjects aged 20–40 years. In
consideration of recent data suggesting gender
differences in substrate utilization, the protein