【单选题】

Recreational runnerCarrie Johnston usually doesn’t feel hungry after a good sweat.Exercise (31) Johnston’ s appetite, but she knows she needs to (32) lost calories following a workout.

"When I come home from a good run, I force myself (33) supper," says Johnston, a dietitian at McMaster University in Hamilton. (34) Johnston says many female athletes let good eating habits go and riskhealth (35) thinness. Johnston, who works in the bone-marrow transplant unit at McMaster, has a background in sports (36) . In 1997, while a student at the University of Guelph, she worked with Prof. Heather Keller on a study for her (37) on the eating habits of female (38) .
The (39) person with eating disorders is driven by a desire to look svelte, says Johnston.But her study focused on athletes who eat less to lower weight and body fat (40) the belief it will improve (41) .
The study involved (42) . 22 elite female athletes between (43) 15 and 25 over three months. "Years ago when we didn’t know any better it was thought that being lighter meant running (44) ," says Johnston, adding that’s still the mentality of many competitive runners, as well as other (45) like gymnasts and swimmers. JoB、nation’s study (46) consumed 400 to 700 fewer calories daily than recommended for their (47) training.
Even when training more, as they got closer to competing, they failed to (48) more food fuel for energy. Initially, race (49) tend to improve when a runner loses some weight, but then they hit a peak and (50) , says Johnston.
A．to eat
B．eating
C．eat
D．ate