As a treatment for severe obesity, bariatric weight loss surgery's popularity is growing. When diet and exercise fail the more than 60 million Americans considered obese, surgery, for some, can literally be lifesaving.

But it isn't for everyone. While generally safe, bariatric weight loss surgery (also called weight loss surgery) has risks. And losing weight after bariatric surgery is far from automatic; it takes commitment to lifelong changes in eating patterns and lifestyle.

According to the National Institutes of Health, weight loss surgery might be a choice for you if you meet the first or second of the following criteria and criteria three, four, and five:

Bariatric Weight Loss Surgery: Are You a Candidate?

1. A body mass index (BMI) greater than 40.

For example, your BMI is greater than 40 if you are:

• Five feet six inches tall and weigh more than 248 pounds,
• Five feet nine inches tall and weigh more than 270 pounds, or
• Six feet tall and weigh more than 295 pounds.

You can calculate your body mass index using a BMI calculator on WebMD.

2. Your BMI is greater than 35, and you have obesity-related health problems that may improve with weight loss.

Obstructive sleep apnea, severe arthritis, and diabetes are several conditions that may benefit from even a small weight loss. Weight loss surgery can dramatically reverse these health problems when caused by obesity.

3. You can demonstrate that traditional weight loss programs like diet and exercise haven't worked.

It's by far preferable to lose weight without surgery's risks. Weight loss surgery should be considered a last resort after traditional methods fail. Some centers may require you to show you have made serious efforts to lose weight.

4. You are ready to commit to permanent lifestyle changes after surgery.

Weight loss surgery is no quick fix. Ideally, surgery is only the beginning of a new healthy lifestyle.

5. You understand the risks and benefits of bariatric weight loss surgery.

As with any surgical procedure, it's essential to be well-informed before considering weight loss surgery -- knowing and accepting the risks as well as the benefits.

Bariatric Weight Loss Surgery: Benefits

The primary benefit of weight loss surgery is easy to understand: weight loss!

• Gastric bypass surgery causes an average loss of 61% of excess weight.
• Gastric banding surgery causes slightly less -- an average of 47% of excess weight lost.

Improvements in general health are also common. Obesity-related medical conditions usually improve or even go away after weight loss surgery, including:

• Diabetes
• Severe arthritis
• Obstructive sleep apnea
• High blood pressure

About 95% of people report improved quality of life after weight loss surgery. Some studies also suggest people live longer after weight loss surgery, compared to equally obese people who do not have surgery.