the space of 3–4 days) by a combination of sweat-
ing and severe restriction of food and fluid
intake. This practice of making weight may be
repeated very often in a competitive season, as
the lost weight is quickly regained. A more
gradual weight loss (3–4 kg over 3–4 weeks)
achieved by a more modest restriction of energy
intake and increased energy expenditure would
probably allow a better hydration state to be
maintained. Prolonged dietary restriction,
however, would inevitably involve restriction of
protein and carbohydrate intake, and might lead
to some loss of body proteins and glycogen
stores. Although dehydration has a much
smaller impact on high-intensity exercise than on
endurance activities, and does not seem to
compromise muscle strength or performance in
events lasting less than 30 s, some reduction in
function may occur (Sawka & Pandolf 1990).
Dehydration is better tolerated by trained
athletes than by sedentary individuals, with
less impact on thermoregulation and exercise
performance (Sawka & Pandolf 1990). The
trained person has an increased body water
reserve, and may be able to tolerate a fluid deficit
of up to 5% of body mass without a significant
detrimental effect on some aspects of physiologi-
cal function (Rehrer 1991).
Athletes should be encouraged to maintain
a relatively stable body weight and to lose
unwanted fat gradually. The practical experience
of athletes and coaches, however, indicates that
the most successful performers often undergo
severe weight-loss regimens in the few days
before competition. The use of diuretics, and
competition after their use, is to be discouraged.
Not only does this impair performance, but also
poses a health risk.
Gaining weight
A high body mass is an advantage in many
sports, including the throwing events in athlet-
ics, and the top weight categories in weightlift-
ing, wrestling and judo. If too much of this
weight is made up of fat, however, performance
will suffer. The principles of weight gain are the
same as those for weight loss: a positive energy
balance will result in weight gain, and a negative
energy balance will result in weight loss. Athletes
who are seeking to gain weight should strive to
ensure that as much as possible of the gain is in
the form of lean tissue. This can be achieved most
effectively through a vigorous weight-training
programme that stresses the large muscle groups
in the legs, hips, shoulders, arms and chest.
Increases in muscle mass occur only slowly, and
may take many years to be fully realized, but this
is preferable to the increase in body fat that is
quickly added by the use of high-energy weight-
gain supplements.
Eating a high-protein diet will not in itself
result in an increase in muscle mass (Lemon
1991). Any protein consumed in excess of the
body’s requirement will simply be used as a fuel
for oxidative metabolism, and the excess nitro-
gen will be excreted. The common practice of
eating large amounts of meat, dairy produce and
eggs is expensive, and is potentially detrimental
to the athlete’s health and performance. Abnor-
mal eating habits established during the years of
training are not easily altered in later life, and
consumption of a relatively high fat diet, which
almost invariably accompanies a high intake of
these foods, may lead to an increased risk of car-
diovascular disease. In addition, if the intake of
protein and fat is too high, there will be little
room left in the diet for high-carbohydrate foods.
Without an adequate dietary carbohydrate
intake, the athlete is unlikely to be able to train to
full potential and will be unable to maximize the
benefits that accrue from consistent intensive
training.
Many weightlifters and bodybuilders use spe-
cific amino acid supplements in an attempt to
stimulate output of growth hormone and insulin,
as both of these hormones are involved in the
stimulation of protein synthesis and thus in the
processes of muscle growth and repair. In a care-
fully controlled trial, however, supplementation
with the amino acids that are purported to be
effective at a dosage equal to that commonly
used by power athletes (1 g arginine, 1 g
ornithine and 1 g lysine, twice daily), had no