context: Losing weight takes work. But when you have a lot of weight to lose, and if exercise and diet aren't enough, you might consider weight loss surgery, also called bariatric surgery. You'll probably have questions about how much it costs, what insurance covers, and how to convince your insurance to cover the bill. Here's what you should know. Weight loss surgery is expensive. Typical costs can run from $20,000 to $25,000, according to the National Institute of Diabetes and Digestive and Kidney Diseases. The price of your weight loss surgery will depend on several factors: The type of surgery you're having. Types of weight loss surgery include gastric bypass, adjustable gastric banding, vertical gastric banding (also called stomach stapling), sleeve gastrectomy, and biliopancreatic diversion. Other options include intragastric balloons or even an electric Implant device. Each has a different fee. Your surgeon's fee. This will vary based on where you live, your surgeon's expertise, and the procedure's complexity. The hospital you choose. Costs will vary and may include the operating and hospital rooms, among other fees. Additional costs may include: Anesthesiologist's fee Surgical assistant's fee Device fees Consultant fees (if necessary) Follow-up procedures (for the gastric band) If you have health insurance, read your policy carefully, and work closely with your insurer and your doctor to see what's covered. Under the Affordable Care Act, some states require that health insurers selling plans in the Marketplace or directly to individuals or small groups cover bariatric surgery; by 2016 nearly half of states mandated coverage for these plans. Most insurance companies recognize that people who are overweight and obese are more likely to get serious health conditions such as type 2 diabetes, high blood pressure, heart disease, high cholesterol, and sleep apnea. If you don't have health insurance, have insurance through a large employer (50 or more employees), or you live in a state that does not include bariatric surgery in its essential health benefits, you'll likely have to pay the entire bill yourself. Some weight loss surgery centers can help you get a loan that you can repay over a number of years. Most major insurance companies will require: Proof that surgery or medical intervention is medically necessary. Your surgeon can help provide your medical history and documentation of your weight-related health problems. Participation in a physician-supervised diet program. You may be required to successfully complete a 6-month weight-loss program before approval is granted. Medicare does not require this 6-month program, but you may be encouraged to participate anyway. This type of diet program involves monthly visits to your doctor or bariatric surgeon's office for 6 months. The insurance companies aren't trying to find out if you can lose weight through dieting. In fact, most insurance companies require that the patient's weight be stable during this time -- with no up-and-down fluctuations -- or you may be denied coverage. They want you to demonstrate over the 6 months prior to surgery that you can commit to lifestyle changes you'll need to make forever after your weight loss surgery. A psychological evaluation. This is to make sure that you understand weight loss surgery and the impact it will have on your lifestyle. The psychological evaluation also checks for untreated binge eating or any other psychological issues. A nutritional evaluation. You will work one-on-one with a nutritionist to outline specific dietary changes and habits that need to be changed. When you have completed these steps, the surgeon will send a preauthorization request letter to your insurance company. The letter will outline your medical history and health problems related to your weight, and provide documentation that you have completed all requirements for approval. The insurance company will then review your case. If you have symptoms of weight-related conditions, the company may request specific diagnostic tests, such as cardiac, pulmonary, or sleep apnea evaluations. During this period, keep accurate notes of all communications between the insurance company and your surgeon. Keep copies of completed insurance forms, letters sent, and letters received. If your request is turned down, or if the insurance company agrees to pay only a small percentage of the cost, the door is not closed. You can write a letter of appeal to the insurance company representative (such as a claims supervisor) who signed the denial. Before you appeal, make sure you understand your policy completely, and that it does not specifically exclude the weight loss surgery you want. Also, make sure restrictions were not in place when you first began your contract with the health plan. Your appeal letter should include: An explanation of why you feel the procedure should be covered A request for a full explanation of why coverage is being denied (or paid at a reduced level) A request for a copy of the specific statement -- taken from the policy or benefits booklet -- that explains why your coverage is limited or denied A copy of the denial notification A copy of your doctor's preauthorization request letter You may find it helpful to send a copy of your appeal letter to your state's insurance commissioner or the department of corporations if you are covered by an HMO plan. You can explain that you're having trouble, and ask for assistance. Your bariatric surgeon can help you with your appeal. If you do not have health insurance, or if your insurer will not cover weight loss surgery, talk to your doctor and your surgeon about financing plans. Check on the interest rate, and make sure you are OK with all of the terms.