Final answer:
An exercise physiologist is the scientist who studies how the body uses foods and fluids during a marathon to optimize athletic performance and recovery. They delve into the mechanics behind physical exertion and recovery, aiming to set new records in their field.
Step-by-step explanation:
A scientist interested in how the body utilizes foods and fluids during a marathon run is likely an exercise physiologist. Exercise physiologists focus on understanding the physiological mechanisms underlying physical activities. They study how different foods and hydration levels affect athletic performance and recovery, aiming to optimize these factors for better athletic performance and setting new records for themselves during recovery time.