carol eats 800 kcalories a day to lose weight. she is 40 years old. carol has been walking briskly 60 minutes daily for the past 2 months. in her younger days, she lifted weights but sh has lost considerable lean body mass over the years because of inactivity. recently, carol was diagnosed with hypothroidism, which lowers metabolism. which of the following factors increases carol's energy output and promotes weight loss?