Nutrition in Combat Sports

2 Making Weight in Combat Sports 27
is required to oxidize 1 kg of fat and thereby reduce body weight by 1 kg. This will
take approximately 1 week to accomplish using a proper diet and physical training
program; a relatively slow process that requires sustained discipline. In contrast, an
athlete need exercise only for an hour to generate 580 kcal of heat that requires at
least 1 l of sweat (~1 kg of weight) be evaporated to maintain body temperature
[13] . Disregarding other outcomes and effects of the fluid loss, the athlete is likely
to opt for the latter approach, i.e., use some form of dehydration.
The approaches used to dehydrate include active (exercise-induced sweating) and
passive water loss (sitting in a sauna) [1, 2, 11] . Fasting and food restriction are
practiced to avoid adding mass to the intestinal tract particularly within the last 24 h
before the official weigh-in [2] . This can also have the effect of helping deplete body
glycogen stores and further reduce body weight when water is released as the
remaining stored glycogen is oxidized during exercise. Less common methods
include catharsis through diuretics or laxatives [1, 2, 11, 14] . In a rare report, athletes
were described to have blood withdrawn to induce hypovolemic hypohydration to
help make weight. The blood is reinfused after the weigh-in [15] .
A case study from our lab shows the efforts of two adolescent wrestlers of similar
initial weight and body composition. Data are presented in Table 2.3 and Fig. 2.1.
These athletes relied on physical training and food restriction to reduce body weight.
One wrestler reduced his weight by approximately 6.7% of body weight during the
course of 5 days. The other wrestler reduced his weight by only 2.5%. The fluid
turnover rate as measured using deuterium oxide is remarkably low in the weightreducing
athlete during dramatic weight loss. There is a simultaneous increase in
urine specific gravity reflecting progressive dehydration. In both wrestlers, body fat
stores, estimated using skinfold thickness, changed minimally (from 7% to 6.9% in
the weight loss wrestler and from 9.2% to 8.3% in the weight maintenance wrestler);
hence, primarily fluid loss and possibly some loss of lean body mass allow the
athlete to achieve the weight class. Even the wrestler maintaining weight relied on
dehydration to make weight based on the rapid loss in between day 4 and 5, based
on the increased USG and minimal loss of body fat.
Table 2.3 Case study of making weight in adolescent male wrestlers
Weight-losing wrestler (WL) Weight-maintaining wrestler (WM)
Age (years) 16.5 17.5
Initial mass (kg) 54.4 55.5
% fat a 7 9.2
Initial TBW (L) b 36.8 37.0
Weight class (kg) 50.9 54.1
% mass reduction 6–7 2.5
Fluid turnover (L/day) c 0.9 2.25
aCalculated using an equation [85] for skinfold thickness that has been validated for adolescent
wrestlers [86]
bMeasured using deuterium oxide dilution [87]
cCalculated using the two-point method described by Wolfe [87]