First and foremost you must understand losing her weight is a very gradual process. She should have strong determination and patience if you want to lose weight. And it cannot happen suddenly. Losing too mich suddenly is also not good for health. She has to follow a strict diet and exercise schedule. Regarding diet - have small multiple meals instead of 3 big meals, eat food rich in proteins and fibres like egg white boiled chicken vegetables fruits pulses, avoid carbohydrate rich foods like rice curds oily foods sweets ghee and other junk food. Regarding exercises - start slowly with brisk walking, then change over to jogging,and other abdominal exercises. Never over strain.. And always keep herself well hydrated and enjoy whatever she does...consult dietitian they will do the needful.