All told, it can take about six to nine months or so. You’ll start with three to four weeks of orientation, paperwork and other tasks. Then you’ll be evaluated by a nurse practitioner. Once that appointment happens, your surgery will typically be scheduled for four to six months later.

During these months, you’ll be on a weight-loss program. You’ll also meet with a dietitian, psychologist, physical therapist and your surgeon. You might have exams with other specialists. Learn more about Considering Bariatric Surgery.

Dieting is rarely effective long term for biological reasons, studies show. When you lose weight by dieting, you burn fewer calories because you use less energy. Your body, interpreting less food as a source of stress, also slows down.

Your digestive system sends more hunger signals to your brain, spurring your appetite. Exercise doesn’t always help much because it accounts for only a portion of the calories you burn.

No. Risk of death from bariatric surgery is very low, even though many patients have serious health conditions at the time.

In addition, obese people who get surgery lower their risk of early death from any cause by as much as 89 percent, research suggests. That’s particularly true for those who have obesity-related conditions such as Type 2 diabetes and heart disease.

One study followed about 8,400 patients who had surgery and about 25,000 similar patients who were instructed only in changing diet and behavior. Over 10 years, the patients who had surgery had about half the risk of dying as the other patients. The study was published in 2018 in the Journal of the American Medical Association.

This is unlikely. Studies show a large majority of patients who get bariatric surgery lose at least half their excess weight and keep it off for years. Even the 10 to 15 percent of patients who do not lose at least half their extra weight see health benefits.

Yes. It will make your operation safer by reducing belly fat and shrinking your liver. You will also start to learn the eating and exercise habits you’ll need after surgery.

Yes. You’ll have to take vitamin and mineral supplements for life because your body won’t absorb nutrients the way it used to. You’ll need at least yearly tests to measure your levels of iron, calcium, vitamin D and other elements. The amounts and types of supplements you take may change over time.

You will probably develop loose skin as you lose weight. Deciding on plastic surgery to remove the excess skin is a highly personal decision, however. It will depend on how you feel after your weight loss. You may have to wait at least 18 months after your operation to have plastic surgery.

Some hair thinning is common three to six months after bariatric surgery, although it’s unclear why. The hair loss is usually temporary. Getting enough protein, vitamins and minerals can help it regrow.

You will be permanently more sensitive to alcohol after bariatric surgery. You will feel effects with fewer drinks. A small percentage of patients say they have alcohol abuse problems, though most had the problem before surgery as well.

The American Society for Metabolic and Bariatric Surgery recommends that you:

• Don't drink while you are losing weight fast, such as in the six months after surgery.
• Be aware that even small amounts can make you intoxicated.
• Don't drive or operate equipment after drinking any amount.
• Get help if drinking becomes a problem.