Exercise and activity can help you lose weight, and they are
generally part of a weight-loss program. However, some dangers are involved
both for those just beginning a fitness program and those who are active and
In order to lose more weight, or to lose weight more quickly, people
beginning a fitness program sometimes restrict calories too much (eat too
little). Because you need calories when you are active, this can lead to
Fit people usually have a higher-than-average ratio of muscle to fat.
Muscle weighs more than fat, so people who have more muscle than average may
weigh more than another person with the same stature. In order to lose what
seems like extra weight, some people restrict calories even when they are
burning more calories than most people with the same weight and stature. This
also can lead to inadequate nutrition.
Rapid weight loss has dangers. It appears to lead to the development
of eating disorders, illness, and injuries and may delay growth in young
people.1 Gradual weight loss is healthier than rapid
weight loss, but for people who already have minimal body fat, even gradual
weight loss may be unhealthy because the body will burn muscle when it has no
excess fat at all. It's healthier to get to an appropriate weight and maintain
it whether you are training or performing or in off-season.
Rapid weight loss is often seen in those who participate in:
Activities like ballet and gymnastics, where
appearance is considered very important. The reasons for this practice are
often based more on social pressures than on health or
Sports with weight classifications, such as wrestling.
You may be tempted to lose weight rapidly to "make weight" (qualify in a weight
class that is lower than your weight during training).
Some athletes and coaches believe that training at a higher weight
and then dropping weight right before competition improves performance. There
is little concrete evidence to support this.
Reimers KJ, et al. (1996). Sports nutrition. In MB
Mellion, ed., Office Sports Medicine, 2nd ed., pp.
22-31. Philadelphia: Hanley and Belfus.