Medicare covers weight reduction surgery, but only under specific conditions

Medicare Part B covers bariatric surgery — the medical term for weight reduction procedures — when your doctor documents that you meet strict medical criteria. The surgery must be medically necessary to treat a related health condition, not purely for appearance. Medicare will not pay for weight loss surgery done only for cosmetic reasons or general weight management.

The most common covered procedures are gastric bypass, gastric banding, and duodenal switch. Medicare also covers some newer procedures, though coverage rules change. Your surgeon's office should verify coverage before scheduling, because the rules differ based on your specific situation and which Medicare plan you have.

Key Takeaways

  • Medicare Part B covers weight reduction surgery only when you have a BMI of 35 or higher with an obesity-related condition, or a BMI of 40 or higher regardless of other conditions.
  • Your doctor must document that you have tried medical weight loss (diet, exercise, medication) for at least three months before surgery can be covered.
  • You must complete a psychological evaluation showing you understand the surgery and can follow the required diet changes afterward.
  • Medicare requires the surgery to be performed at a center that meets specific accreditation standards, so not all hospitals may have access to.
  • Your surgeon's office should submit a coverage request to Medicare before your surgery date to confirm what will be paid.

The medical requirements Medicare uses to decide coverage

Medicare uses your Body Mass Index (BMI) as the starting point. You must have a BMI of 35 or higher and at least one obesity-related condition — such as type 2 diabetes, heart disease, high blood pressure, or sleep apnea — or a BMI of 40 or higher with no other conditions required.

BMI is calculated from your height and weight. A BMI of 35 means you are roughly 60 pounds overweight if you are 5 feet 5 inches tall, though the exact number varies by height. Your doctor's office can calculate yours, or you can use the BMI calculator on the National Institutes of Health website.

Meeting the BMI threshold is only the first step. Medicare also requires that you have tried to lose weight through medical management — meaning diet, exercise, and sometimes medication — for at least three months before surgery. Your doctor must document these attempts in your medical record. This is not a waiting period you sit through; it is proof that you worked with your doctor on weight loss before considering surgery.

The psychological evaluation and informed consent requirements

Before Medicare will cover the surgery, you must complete a psychological evaluation by a mental health professional. This is not a test you can pass or fail. The evaluator is checking that you understand what the surgery does, what changes you will need to make afterward, and whether you are ready to follow the required diet for the rest of your life.

After weight reduction surgery, you will eat much smaller portions and must take vitamin supplements permanently. Some people experience nausea or dumping syndrome (rapid stomach emptying that causes sweating, dizziness, and cramping). The psychological evaluation makes sure you know these realities before you commit to surgery.

You will also sign an informed consent form stating that you understand the risks and benefits. Medicare requires this documentation in your file before the surgery date.

Which hospitals and surgery centers Medicare will pay for

Medicare will only pay for weight reduction surgery performed at a center that holds accreditation from one of these organizations: the American College of Surgeons Commission on Cancer, the American Association for the Surgery of Trauma, or the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP).

This means not every hospital that performs bariatric surgery qualifies for Medicare payment. If your surgeon operates at a non-accredited facility, Medicare will not cover the procedure, even if you meet all other requirements. Ask your surgeon's office whether their facility holds one of these accreditations before you schedule surgery.

Some surgeons operate at multiple facilities — one accredited and one not. Make sure you know which location your surgery is scheduled at, and confirm with Medicare that it qualifies.

What happens after Medicare approves the surgery

Once your doctor submits your medical records to Medicare and receives approval, you will typically pay your Part B deductible (which changes each year) and then 20 percent of the approved amount. The surgery center will bill Medicare for the rest.

If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs may be lower. Medigap plans often cover the 20 percent coinsurance. Medicare Advantage plans have their own rules and may require prior authorization, so check with your plan before scheduling.

The approval process usually takes two to four weeks. Your surgeon's office handles the paperwork, but you should follow up if you do not hear back within that timeframe.

What to ask your doctor before pursuing surgery

Ask your surgeon whether they have performed this procedure at least 50 times and what their complication rate is. Ask whether the facility is accredited by one of the three organizations Medicare requires. Ask what the total cost will be, what Medicare will cover, and what you will owe out of pocket.

Ask your surgeon what happens if you regain weight after surgery, and whether they offer follow-up support. Ask about the vitamin supplements you will need to take for life and what they cost. Ask whether the facility offers a support group for patients before and after surgery.

Ask your primary care doctor whether weight reduction surgery is the right choice for your specific health conditions, and whether there are other treatments you should try first. Some conditions improve with medication or other approaches before surgery becomes necessary.

When Medicare will not cover weight reduction surgery

Medicare will not cover the surgery if your BMI does not meet the threshold, even if you have serious weight-related health problems. You will not may have access to if you have not tried medical weight loss for at least three months. Medicare will not pay if the surgery is performed at a non-accredited facility.

If you do not complete the psychological evaluation or if the evaluator has concerns about your ability to follow the required diet changes, Medicare may deny coverage. If you have certain medical conditions that make surgery too risky — such as severe heart disease or liver disease — your doctor may recommend against it, and Medicare will not cover it.

If you are denied coverage, you have the right to appeal. Your surgeon's office can help you file an appeal and submit additional medical information if your situation has changed.

Frequently Asked Questions

Does Medicare Advantage cover weight reduction surgery?

Medicare Advantage plans must cover the same bariatric surgery that Original Medicare covers, but they may have different rules about which facilities may have access to or require prior authorization. Contact your specific plan to ask whether they cover the procedure and what paperwork you need before scheduling.

What if I have already had weight loss surgery and want Medicare to cover a revision?

Revision surgery — such as converting a gastric band to a bypass — may be covered if you meet the same medical criteria as primary surgery. Your surgeon will need to document why the first surgery did not work and why revision is medically necessary. Submit this documentation to Medicare for review before scheduling.

Can I get weight reduction surgery if my BMI is 33 or 34?

Medicare's rules require a BMI of at least 35 with an obesity-related condition, or 40 without one. If you are below these thresholds, Medicare will not cover the surgery. Some private insurance plans have different rules, so check your plan documents or call the plan directly.

How long do I have to wait after the three-month medical weight loss attempt before I can have surgery?

There is no waiting period after the three months end. Once your doctor has documented three months of medical weight loss attempts, you can move forward with the psychological evaluation and surgery scheduling. The three months is proof of effort, not a calendar requirement.

What if my doctor says I need weight reduction surgery but I do not meet Medicare's BMI requirements?

If your doctor believes surgery is medically necessary despite not meeting the standard BMI threshold, they can request an exception from Medicare. This requires detailed medical documentation explaining why your specific situation warrants coverage outside the normal rules. Your surgeon's office can submit this request, though approval is not certain.