NUTRITION IN SPORT

(Martin Jones) #1

knowing menstrual history will also be impor-
tant in setting weight loss and dietary goals
(Duecket al. 1996).
Body composition should be measured and
weight loss goals centred on the loss of body fat
instead of just weight. This way the goal is
shifted to changes in body composition instead
of weight (Table 35.1). Knowing body composi-
tion also helps prevent the athlete from losing too
much weight or setting an unachievable goal.
This information can then be used to determine
an optimal body weight and to set fat loss goals.
For the athlete who is already lean, yet wants to
diet, this process can help convince him or her


that weight loss is not necessary. Weight loss in a
lean athlete is not possible without seriously
compromising performance because of the
inevitable loss of FFM. These athletes will benefit
more from establishing good dietary practices
than from weight loss. These guidelines can also
be used with the young athlete who does not
want to gain weight even though growth and
weight gain should be occurring.

Role of diet
If the athlete does need to lose weight (body fat),
a weight loss plan needs to be developed early
in the athlete’s training programme to avoid
potentially harmful dieting practices and weight
cycling. Weight loss is not recommended during
periods of intense endurance training; athletes
cannot be expected to train intensely and
improve performance on low energy intakes.
Thus, weight loss goals should be set at approxi-
mately 0.5–1 kg · week–1, depending on body size
and gender, and focus on decreases in body fat,
while maintaining or increasing FFM (Wilmore
1992b; Fogelholm 1994). The degree of energy
restriction will depend on body size, typical
energy intake and expenditure, and the period
allotted for weight loss. In general, reducing
energy intake by 10–25% (approximately
1680–3360 kJ or 400–800 kcal daily) may be all
that is necessary. If the weight loss is occurring in
the off season, then both the restriction of energy
intake and increased energy expenditure need to
occur.
Severe energy restriction or fasting should not
be used with athletes. This approach to weight
loss only decreases carbohydrate and protein
intake and, thus, the ability to replace muscle
glycogen (Bogardus et al. 1981) and repair and
build muscle tissue after exercise. These types of
diets also increase the risk of injury and the feel-
ings of fatigue after routine workouts, which in
turn can dramatically undermine self-confidence
and performance. Finally, these diets increase
FFM losses and decrease RMR (Donnelly et al.
1994; Thompson et al. 1996). These factors,
combined with the feelings of deprivation that

the overweight athlete 479


Table 35.1Ranges of relative body fat for men and
women athletes in various sports. From Wilmore
(1992b), with permission.


Sport Men Women


Baseball, softball 8–14 12–18
Basketball 6–12 10–16
Body building 5–8 6–12
Canoeing and kayaking 6–12 10–16
Cycling 5–11 8–15
Fencing 8–12 10–16
Football 6–18 —
Golf 10–16 12–20
Gymnastics 5–12 8–16
Horse racing 6–12 10–16
Ice and field hockey 8–16 12–18
Orienteering 5–12 8–16
Pentathlon — 8–15
Racketball 6–14 10–18
Rowing 6–14 8–16
Rugby 6–16 —
Skating 5–12 8–16
Ski jumping 7–15 10–18
Skiing 7–15 10–18
Soccer 6–14 10–18
Swimming 6–12 10–18
Synchronized swimming — 10–18
Tennis 6–14 10–20
Track and field
Field events 8–18 12–20
Running events 5–12 8–15
Triathlon 5–12 8–15
Volleyball 7–15 10–18
Weightlifting 5–12 10–18
Wrestling 5–16 —

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