An individual’s Body Mass Index (BMI) is a formula that takes your height and weight into consideration. To have weight loss surgery (and to have your insurance company cover the cost), a patient needs to have a body mass index of 40 or greater if they have no medical problems. Insurance may still cover weight loss surgery with a BMI as low as 35 or greater if the patient has medical problems that are related to their weight, such as diabetes, high blood pressure, high cholesterol, and/or sleep apnea.