Hi Olivia,
There is something called ENERGY BALANCE EQUATION which states that body mass remains constant when caloric intake equals caloric expenditure.Any imbalance on either the energy output or input side of the equation causes the body mass change.
There are 3 ways to imbalance the energy balance equation in the direction of weight loss:
*Decrease caloric intake below the daily energy requirement i.e. diet modification.
* Maintain normal caloric intake and increase energy expenditure through additional physical activity, exercise.
* Combined both methods by decreasing daily caloric intake and increase energy expenditure i.e. diet modification and exercise.
Weight loss plan cant be generalized it varies from person to person depending on individuals health status,age,body type etc.See to it you do proper weight loss plan that suits you.
Take care.