The answer to that question is different for each individual. Differences in weight, age, metabolism, how strenuous one's work is, and other factors must all be considered. But, in general, for a woman weighing 50 kilograms, an estimate of about 1,500 calories a day shouldn't be too far off the mark.
答案因人而異，要視體重、年齡、代謝能力、從事的工作強度等條件而定，不過一位五十公斤的女性，一天一千五百卡上下應該不太離譜。