Why diet especially energy intake should be related to age sex and activity of a person?

Diet, particularly energy intake, should be tailored to an individual's age, sex, and activity level because these factors significantly influence metabolic needs and overall health. Younger individuals and those who are more physically active typically require higher energy intake to support growth, development, and energy expenditure. Conversely, older adults may need fewer calories due to a slower metabolism and decreased physical activity. Additionally, men generally have higher caloric needs than women due to differences in muscle mass and hormonal influences.