The verdict is in: weight loss surgery isn't a 'magic bullet'.

Bariatric surgery isn’t all that it appears to be. Stories like the one we saw this week on A Current Affair show it to be some sort of magic bullet when it comes to weight loss, however studies have shown these procedures may not be the cure-all for Australia’s obesity problem some believe it to be.

According to Prevention, within the first two years of surgery patients typically lose 75 per cent of the extra weight they were carrying, however five years out 85 per cent of patients “have regained about half of the weight they’ve lost.” The other 15 per cent have gained back even more.

That’s because the psychology behind weight gain and loss still isn’t well understood.

The Alfred Hospital in Melbourne has announced free bariatric surgery for some obese patients. Normally the cost of the surgery is as much as $20,000. Dr. Paul Burton from the hospital says the surgery literally changes patients lives overnight, but for how long?

“Patients come back to the clinic and often you can’t recognise them,” he told A Current Affair.

Single mum Lauren is one of the patients receiving free bariatric surgery at The Alfred Hospital in Melbourne. Video courtesy of A Current Affair.

Single mum Lauren Hill, 27, sold A Current Affair her breaking point came when she began walking 10 kilometres a day and only lost one kilo. She says she thought, “Why me? Why can’t I lose weight?” Now she feels hopeful thanks to Dr. Burton’s free lap band surgery.

A cautionary tale, one of many, is that of singer Carnie Wilson of Wilson Philips famously filmed her first weight loss surgery in 1999 only to regain the weight and undergo a second procedure 2012. She told People, “I’ve really struggled since I’ve become sober. How do I balance that? How can I relax and not overeat? Because I have a lot of pressure in my life. I’m a working mother … You try to pay the bills, you try to keep your life going and there’s pressure.”

Wilson has also blamed her weight gain on her two pregnancies, saying, ““Having children derailed me a bit.”

A 2006 study into weight gain after gastric bypass surgery found that patients who regained large amounts of weight reported eating almost as much as before the operation.  “This increase in intake takes place over several years and does not occur suddenly.”

Bariatric Surgery Source reports the success rate for such surgeries at 50 per cent. "The good news is that most patients (about 80% of morbidly obese and 65% of super obese) keep at least 50% of their excess weight off after 10 years."

The failure rate of traditional diets varies from 65 per cent to 95 per cent, depending on which source you use. Researchers at the University of California at Los Angeles analysed 31 long-term diet studies and found that about two-thirds of dieters regained more weight within four or five years than they initially lost.

There are other complications relating to bariatric surgery. Some patients suffer ill-effects for weeks if not months, not able to keep any food down at all and vomiting up solid foods for longer than anticipated. Others have reported nutritional deficiencies resulting in hair loss.

Two former work colleagues of mine had weight loss surgery and while initially successful, the weight eventually crept back on, despite one of these colleagues attending group counselling sessions in an attempt to adjust to his new way of life.

Bariatric Surgery Source cites four many indicators of weight loss surgery success:

Demonstrating the ability to lose weight ahead of the procedure;

Addressing any other substance abuse issues;

Ensure they have a good support system to go home to;

Seeking psychological advice.

One of my former work colleagues who had the surgery told me about other patients who were struggling to accept their new bodies, with one man drinking oil in a desperate attempt to regain the weight he had grown used to and another drinking cream.

Some patients transfer their addiction to food to other consumables or activities such as alcohol, a common substance that is abused especially right after surgery when very little food can be consumed.

Others report sex addictions, chronic gambling habits or even compulsive shopping.

In 2012 a study examined the prevelence of alcoholism after bariatric surgery, reporting that the percentage of patients abusing alcohol increased from 7.6 per cent before surgery to 9.6 two years after surgery. The study, which was published in the Journal of the American Medical Association, also found that the effect continues even a decade after the surgery.

Scientists aren't sure why this occurs.

“Whether it’s addiction transfer or something else going on, we really don’t know at this point,” said James Mitchell, a doctor and professor of neuroscience at the University of North Dakota.

The consensus seems to be that weight loss surgery alone isn't the solution to the problem of obesity. Neither is dieting. Each experiences a "honeymoon period" after which the risk of regaining weight increases, not because of issues with metabolism, not due to the so-called famine-response of bodies, but because breaking old habits is hard. You can't just go back to how you used to eat.