The factors that contribute to the amount of calories a person burns are age, gender, body size and makeup. According to Healthy Living at AZ Central, the larger a person is the more calories he burns. A heavier person naturally expends more calories than a lighter person.
The more a person weighs, even if the weight is not all muscle, the more calories he burns. For example, a 125 pound person that walks 3.5 miles per hour typically burns only 120 calories, whereas a 185 pound person burns approximately 178 calories for the same activity. Also, according to AZ Central, males generally burn more calories than females; and young people generally burn more calories than older people.