An average person eats about 2000 calories a day, according to a study conducted by the University of Westminster's Human Performance Laboratory. The six women studied consumed between 1770 to 2600 calories a day, as published in the Mirror.
According to the National Institute of Health, how much a person needs to eat depends on her activity level. A woman should eat 2000 to 2200 calories if she has an active lifestyle but only 1600 calories a day if she has a low level of physical activity. Similarly, a man who has a low level of physical activity needs only 2000 calories a day but needs to consume up to 2800 calories if he has an active lifestyle.