These numbers remain estimates, as they hide wide variations among individuals. The main reason for the higher calorie needs of men is that they, on average, have greater muscle mass, which raises their basal metabolic rate — the amount of energy the body burns at rest. Men typically require more daily calories than women, but this is not an absolute rule, as energy needs are influenced by several factors, primarily body composition, basal metabolic rate, and level of physical activity, according to nutrition experts. General dietary guidelines suggest that the average daily energy requirement for adults aged 19 to 64 is about 2,000 calories for women and 2,500 for men, with these figures gradually decreasing after age 65. However, a comparison between a man and a woman of the same height, weight, age, and activity level may reveal a difference in calorie needs due to differences in body composition. This rule does not negate individual differences; a woman with high muscle mass may need more calories than a man who is less active or has less muscle. Muscles burn more calories than fat even without physical activity, which explains the gender difference in energy expenditure. These differences in muscle mass are linked to hormones, as testosterone, which is present at higher levels in men, promotes muscle growth. Furthermore, long-term, strict diets can lower the basal metabolic rate, reducing the body's energy needs. Experts confirm that determining daily calorie needs is not based on general averages alone but requires considering age, body composition, physical activity level, and health status, while medical guidelines provide tools to help estimate these needs more accurately.
