Its not nearly that simple. A person's metabolism rate is not constant -- it varies greatly with activity level, intensity of activity, type of food consumed, and even the weather. Hunger can also vary greatly. A person's fat storage and fat utilization are also influenced by endocrine responses.weight loss is a simple formula.
basal metabolic rate+exercise (includes gym work and any acitvity other than resting)- calories consumed per day.
everytime you reach a 3500 calorie deficit you should lose a pound. now for best results, a slight amount of weight lifting is best to minimize muscle loss.
Bottom line -- its almost impossible to get and remain thin by dieting. You can get leaner by exercising with enough intensity. However, its a lifelong commitment -- as many of us have painfully realized.