Hi I understand your concern. It is always recommended to go for natural way of losing weight by focusing on diet n exercise and lifestyle modification. If you have any necessity to reduce within 10days you can lose upto 2-4 kgs by following a very strict diet, but 18kg is an impractical target for yourself. In this case you can go for different cosmetic surgeries available.
Next Steps
If you want a structured diet designed for your need you can message to me personally through practo.