As more people abandon New Year's resolutions to lose weight and turn to obesity surgery, doctors are debating which type is safest and best.
And researchers are uncovering some surprising trends.
The most common method in the United States - gastric bypass, or stomach-stapling surgery - may be riskier than once thought. Yet surgeons still favor it for people who need to lose weight fast because of heart damage or other serious problems.
A gentler approach favored in Europe and Australia - an adjustable stomach band - can give long-term results that are almost as good and with far fewer risks. It may be the best option for children or women contemplating pregnancy, and is reversible if problems develop.
A radical operation - cutting away part of the stomach and rerouting the intestines - is increasingly being recommended for severely obese people. It gives maximum weight loss but also is the riskiest solution.
A large U.S. government study just got under way to compare all three options.
But regardless of which method is used, studies show an inescapable reality: No surgery gives lasting results unless people also change eating and exercising habits.
"The body just has many ways of compensating, even after something as drastic as surgery," said Dr. Louis Aronne, director of the weight loss program at Weill-Cornell Medical College.
He is president of the Obesity Society, the largest group of specialists in bariatrics, as this field is known. The group's recent annual conference in Vancouver featured many studies on surgery's long-term effects.
Obesity is a problem worldwide. About 31 percent of American adults - 61 million people - are considered obese, with a body-mass index of 30 or more. That's based on height and weight. Someone 5-foot-4 is obese at 175 pounds; 222 does it for a 6-footer.
Federal guidelines say surgery shouldn't be considered unless someone has tried conventional ways to shed pounds and is at least 100 pounds over ideal weight, or has a BMI over 40, or a BMI over 35 plus a weight-related medical problem like diabetes or high blood pressure.
More people are meeting those conditions. A decade ago, less than 10,000 such surgeries were done in the United States. That ballooned to 70,000 in 2002 and more than 170,000 in 2005, says the American Society for Bariatric Surgery.
Doctors disagree over which is better: the most popular method, Roux-en-Y gastric bypass, or the adjustable band, which is rapidly gaining fans. Either can be done through a big incision, or laparoscopically with tiny instruments passed through small cuts in the abdomen.
In gastric bypass, a small pouch is stapled off from the rest of the stomach and connected to the small intestine. People eat less because the pouch holds little food, and they absorb fewer calories because much of the intestine is bypassed. They must take protein and vitamin supplements to prevent deficiencies.
The adjustable band has been available in the U.S. only since 2001 but far longer in Europe and Australia where it is dominant. It accounted for 17 percent of U.S. obesity procedures in 2005.
A ring is placed over the top of the stomach and inflated with saline to tighten it and restrict how much food can enter and pass through the stomach.
Deaths from the procedure are only 0.1 percent compared to about 2 percent for gastric bypass. One recent study of Medicare patients found deaths a year after gastric bypass as high as 3 to 5 percent.
The band's reversibility makes it a better choice for children, some doctors say.
"It's becoming more well-known and more accepted. Patients like it because it's less invasive. It's an easier surgical procedure. It's safer," said Georgeann Mallory, executive director of the bariatric society.
"To me it is a very straightforward decision," said Dr. Paul O'Brien, director of the Centre for Obesity Research and Education at Monash University in Melbourne, Australia. "I would strongly recommend that the consumer consider the safest effective procedure first," which is the band, he said.
American doctors have preferred bypass operations because they produce faster, greater weight loss. But new research by O'Brien and others calls that into question.
Combining results on 23,638 patients in 43 published studies, they found that bypasses beat bands for the first three years but were comparable after seven years, with excess weight loss of 55 percent for bypass and 51 percent for bands.
That impressed Dr. Edward Livingston, chief of gastrointestinal surgery at the University of Texas Southwestern Medical Center and chief of bariatric surgery for the Department of Veteran's Affairs national system.
"I really was not enthusiastic about bands until I came to Dallas from Los Angeles and saw the results from the group that I joined, which where quite good," he confessed. "What you can accomplish in a year with a gastric bypass you can accomplish in five years with a laparoscopic band."
Results would improve if Americans copied the Australians and included in the price of the band any future adjustments, Livingston said.
"A key to the success of banding procedures is the followup and working with a patient on their compliance," he said. "When they come in and they've sort of fallen off the wagon, you adjust the band. It really has an amazing effect."
Bands also appear safer for women attempting pregnancy. Several years ago in Massachusetts, a woman and her 8-month-old fetus died of complications 18 months after gastric bypass surgery. Other pregnancy-related deaths have been reported.
In contrast, another study O'Brien and colleagues presented at the obesity meeting found that pregnancy outcomes for women with stomach bands were comparable to normal-weight women, and better than for obese women without bands.
Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City, did a band operation in October for Long Islander Donna Dotzler, who weighed 279 pounds, but wants to do a more drastic surgery for her husband.
"I gave up on New Year's resolutions maybe five years ago," said Jim Dotzler, who weighs 479 pounds. "I'm a smart guy. If this were a matter of willpower, I'd have taken care of this a long time ago."
The operation Roslin has advised for him is BPD, which stands for biliopancreatic diversion, with or without a second procedure called a duodenal switch. Studies show it can cause loss of up to 80 percent of excess body weight for at least as long as 10 years afterward.
Surgeons remove three-fourths of the stomach to leave a sleeve- or banana-shaped organ that is connected to the small intestine, bypassing more of it than a standard gastric bypass does. It can be done in two operations a year apart to reduce its severity and the chances of death, which can be as high as 5 percent.
The "switch" preserves a valve that controls release of food into the intestines from the stomach. These operations account for nearly 5 percent of U.S. obesity surgeries and are growing.
On the horizon are other approaches, like vagus nerve stimulation, to control impulses to eat, and new drugs like rimonabant, which blocks a pleasure center in the brain that makes people want to munch.
"I see the future as combined therapy," with surgery, medication and other approaches used simultaneously, said Aronne, the obesity society president. "Time will tell what works out best."
Weighing the options for obesity surgery
Here is a comparison of the three most popular surgical procedures for obesity:
ROUX-EN-Y GASTRIC BYPASS
Method: A small pouch is stapled off from the rest of the stomach and connected to the small intestine, keeping people from eating as much and limiting how much food is absorbed and stored.
Cost: $20,000 to $30,000
Hospital stay: 2-3 days
Mortality rate: 2 percent; higher in some studies.
Advantages: Produces loss of 50 to 75 percent of excess body weight in a year; reverses obesity complications like high blood pressure and diabetes.
Disadvantages: Relatively high risk of death. Complications can include malnutrition, anemia, osteoporosis, gallstones, ulcer, infection - and pain, gas and diarrhea from food moving too fast through the intestine.
LAPAROSCOPIC STOMACH BAND
Cost: $17,000 to $20,000
Hospital stay: 1 day or less
Mortality rate: 0.1 percent
Advantages: Safer, fully reversible.
Disadvantages: Slower weight loss - 28 to 65 percent of excess weight at two years; 54 percent at five years (some weight is often regained). Side effects can include vomiting and cramps. Not all insurers pay. Bands also can slip or erode over time, and often need adjustment to stay effective.
BILIOPANCREATIC DIVERSION/DUODENAL SWITCH
Cost: $25,000 to $35,000, depending on whether done in 1 or 2 operations
Hospital stay: 3-4 days
Mortality rate: 2.5 to 5 percent
Advantages: Superior weight loss of 60-80 percent of excess pounds within a year.
Disadvantages: Riskiest in terms of death and malnutrition, because more of the intestines are bypassed. Can cause nausea, abdominal pain, weakness, sweating, diarrhea and odor from persistent gas and loose bowel movements.
Sources: National Institute of Diabetes and Digestive and Kidney Diseases; American Society for Bariatric Surgery; American Journal of Surgery; interviews with obesity surgeons.
On the Net:
Surgery explainer: http://win.niddk.nih.gov/publications/gastric.htm
American Society for Bariatric Surgery: http://www.asbs.org
American Obesity Association: http://www.obesity.org
The Obesity Society: www.naaso.org
Body Mass Index calculator: