I am 5ft9 and i want to lose weight but i don't know what should my normal weight. right now i am 216 and i really want to lose weight.any diet for me?

A couple pounds/wk: Successful (intentional) weight loss requires that a person stick to a plan for months or years. The person must be happy with the foods she gets to eat, so severe calorie restriction is usually unsuccessful. A person can cut back on calories enough to lose 2 pounds a week, and will be more likely to stay with that modest type of plan. One to two pounds a week is about a 35-40 lb loss in 6 months.