You don't require 5 litres of water to detox your body according to modern nutrition ): may be naturopath or ayurvedic treatment suggest- I am sorry, I don't have idea on this. As I advice most of my clients to decide on one goal - your queries say you want to detox and weight loss?? Kindly understand Weight loss is not detox. You are 33 years old and have lot of potential to loss weight until u don't have any medical issues. You also seem to have lot of energy since, 4 hours of walking is not a joke. Kindly consult a qualified fitness expert and dietitian to help you in your weight loss journey.