For the 42% of Americans who live with obesity, diet and exercise alone aren't always enough to reach a healthy weight. If you've been trapped in a cycle of failed weight loss, or your health is compromised, weight loss surgery (also called bariatric surgery) may be an option.

"It's important to understand that obesity is a medical condition that can be managed," explains Dr. Nabil Tariq, a bariatric surgeon at Houston Methodist. "Weight loss surgery is an option to consider for those who qualify, and it's a big decision to make that comes with a lifelong commitment to a healthy lifestyle."

Here are the things to keep in mind about weight loss surgery:

1. There are qualifications to meet to be eligible for weight loss surgery

Do I qualify for weight loss surgery? It's a common question.

Some basic guidelines apply, such as:

• You should be age 18 or older
• You have a body mass index (BMI) of 40 or higher OR
• You have a body mass index (BMI) of 35 or higher and an obesity-related condition, like diabetes, high blood pressure, high cholesterol or sleep apnea
• For insurance coverage, you may need a "letter of medical necessity"

This is just a snapshot. It's a good idea to talk with a weight loss surgeon about your unique situation and all the qualifications.

2. Mindful eating still matters after surgery

Remember that weight loss surgery is only one tool to help you on your journey to lose weight. You'll still need to make lifestyle changes such as diet and exercise along the way. (Related: Eating Healthy: 7 Tips for Getting Started Today)

As part of our program, you'll receive nutritional guidance to create a plan that's right for you. Guidelines typically call for daily consumption of 800-1,500 calories and 60-80 grams of protein while avoiding too many carbohydrates such as bread, pasta and sugar. Foods high in sugar and fat will be reserved for special occasions, and rarely eaten if you have gastric bypass surgery.

Making sure you are getting plenty of vitamin-rich and protein-rich foods is also important.

3. The total amount of weight loss varies

"It's hard to say exactly how much weight you might lose," Dr. Tariq explains. "There are a lot of factors, including the type of weight loss surgery and how closely you follow your new diet after the procedure."

Generally, about 40%-50% of weight is lost and kept off. You'll want to talk with your doctor about what expectations are right for you.

4. There are benefits for physical and mental health

Research shows successful weight loss surgery can help you live longer and reverse obesity-related conditions, such as high blood pressure, high cholesterol, sleep apnea and diabetes. (Related: Is Weight-Loss Surgery Worth It?)

"Not only will your physical health likely improve, but as you start moving and feeling better, your mental health can improve as well," adds Dr. Tariq. "It's a win for your overall well-being."