The main factors contributing to weight loss are food intake and energy balance. There are two types of jobs our body does that help consume energy involuntary exercise (like your heart beating, blinking your eyes etc.) and voluntary exercise (like walking to get a glass of water or completing your daily chores) and then there is exercise, which helps your body use up a lot of energy. Weight loss does not happen overnight, it has to be a lifestyle change which includes healthy eating, exercise and a positive mind set.
Depending on how many calories you consume in the day and the amount of energy your body uses up, the rate at which you will lose weight is determined.