Basic heat (kilojoule) = body weight (kg)
×
84
If you say 47 is kilograms, then you need 3948 kilojoules ≈943 calories.
This is at least the energy you need to consume every day. If you consume less than this basic calorie, you will lose weight in theory.
It is true that you want to be thin, but for adolescent girls, it is recommended not to control energy intake casually, which may affect your growth and development, so it is recommended not to try it easily. If you want to lose weight and don't want to affect your growth and development, I suggest you choose to eat low-calorie and high-nutrient foods and take vitamins, calcium tablets and other drugs under the guidance of a doctor.