consistent with the guidelines above, allow
better recovery/maintenance of muscle glyco-
gen levels during periods of heavy training, there
does not appear to be consistent and significant
enhancement of performance in the high CHO
group at the end of the study period, nor impair-
ment of performance in the moderate CHO
group (for review, see Sherman & Wimer 1991;
Shermanet al. 1993). It has been suggested that
athletes may adapt to the lower CHO intake and
muscle glycogen depletion. However, it is also
possible that the protocols used to measure per-
formance in these studies were not sufficiently
sensitive to detect the differences between the
groups, that the studies were not conducted over
sufficiently long periods to elicit clear differences
in performance, and that the area is confused by
some overlap between what is considered ‘mod-
erate’ and ‘high’ CHO intakes (Shermanet al.
1993). In any case, there is clear proof from
studies of acute dietary manipulation that
endurance and performance are enhanced when
body CHO stores are optimized, and that carbo-
hydrate depletion causes an impairment of per-
formance (see Chapters 6–8). Furthermore, there
is anecdotal evidence, including comments from
the studies above, that athletes complain of
‘tiredness’ and ‘muscle fatigue’ during training
when dietary carbohydrate is insufficient. There-
fore, the recommendation that athletes should
consume a high CHO diet to cover the fuel cost
of their training loads and recovery remains
prudent, and further long-term studies are
awaited to adequately test the benefit of this
strategy.
Conclusion
Dietary CHO is provided by a wide variety of
CHO-rich foods and drinks. There is no univer-
sal system that can adequately describe the
diverse metabolic, functional and nutritional fea-
tures of these various foods. Dietary guidelines
for athletes make recommendations for every-
day intake of CHO as well as CHO intake for spe-
cific situations pre, during and postexercise
sessions. Athletes are encouraged to meet these
guidelines by choosing CHO-rich foods and
drinks that offer appropriate characteristics such
as nutrient-density, desirable glycaemic index,
appeal and practicality according to the require-
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