Just how desperate are you to lose weight - desperate enough to have electrodes implanted in your brain? That's the latest approach to tackling obesity now being tested.
With experts warning of an obesity epidemic, drugs companies and medics have been working on newer and better ways to tackle weight gain.
Most recently, the focus has been on prescription medicines, with the development of pills such as Alli, which work by reducing the amount of fat your body absorbs.
There has also been a rise in the use of gastric surgery - literally re-plumbing people's stomachs so they eat less.
But in the U.S., the latest approach to tackling obesity is even more drastic. Deep brain stimulation (DBS), as it is known, involves inserting electrodes into the brain to deliver tiny bursts of electricity to alter the patient's behaviour.
DBS is already used in the treatment of movement disorders such as Parkinson's disease and dystonia - here it works by blocking the nerve signals causing the spasms.
With obese patients, the idea is to target the hypothalamus, the area of the brain which controls our desire to eat. Basically it works by making the patient feel full.
The new approach is being tested in a U.S. Government-approved trial, which is running for three years.
During the procedure, patients first have holes drilled into their skull. The electrodes are then implanted - these are attached to wires, which are fed across the surface of the brain and under the skin to a small battery implanted under the collarbone.
The operation is performed under local anaesthetic so that surgeons can place the electrodes in the right place, guided by the patient's reactions. The patient is asked whether or not they feel full in order to position the electrodes correctly.
So far, two patients have had the operation, and early indications are 'promising', with both eating less and losing weight.
The surgery was performed by Dr Donald Whiting, a neurosurgeon at West Virginia University Hospital. Dr Whiting admits it is a drastic procedure - 'but obesity is a drastic problem'.
He adds: 'There is a risk of stroke and death from this operation, but this is slight. These patients are probably at greater risk of heart attack and stroke from being obese.'
Only patients who've tried every other treatment, including gastric surgery (such as a gastric band or bypass), are considered for DBS. But Dr Whiting believes the new approach makes greater sense than other surgery.
'If the brain controls intake of food, hunger and metabolism, why not go to the source and readjust the controls rather than take an organ such as the stomach, which is working perfectly well, and try to make it behave differently,' he says.
Furthermore, he points out, as many as 20 per cent of obese people, including those who've had stomach surgery, fail to keep off any weight they initially lose.
Carol Poe, a 60-year-old grandmother from West Virginia, was the second person to have the new treatment. She'd previously had gastric surgery and had gone from an astonishing 44st down to 24st, but then could not lose any more.
'Since having the operation, I definitely feel less hungry and don't have the cravings I used to have,' she says. 'When I do eat, I get full more quickly.'
In the five months since Carol had the electrodes implanted, she has lost a stone in weight.
While this might not sound like a lot, Dr Whiting points out that it can take time to tune the electrodes to the right strength. 'When we get this right, I would expect the weight loss to be more rapid,' he says.
'We are fine-tuning, so that the patient gets sufficient nutrition while losing an acceptable amount of weight each month.
'The weight needs to come off at a steady rate - not too fast and not to slow - depending on the individual patient. Our work so far points to this type of surgery being an effective treatment for those who have reached the end of the road and tried all else.'
During the surgery, Carol was asked if she felt hungry or not to help pinpoint the correct position for the electrodes.
She says: 'I was actually able to experience feelings of hunger and of fullness while Dr Whiting experimented with the best place to put the electrodes.
'Once the electrodes were in the right place, my desire to eat went away. It was amazing going from feeling hungry to feeling full.
'I'm delighted with what's happened so far. Now I'm hoping to start losing some serious weight.' But critics argue that DBS is a step too far. As Dr David Ashton, one of the UK's leading experts in obesity treatment, says: 'Going into the brain carries a degree of risk - such as life-threatening infection and stroke - and you would question using it to treat obesity when there are less drastic options such as a gastric band.
'This sort of operation might have a place as a treatment of last resort if other methods fail. But I'm not convinced I would want to advocate it to any of my patients.' Other experts question how effective the treatment will be.
'I think tinkering with the brain might prove too difficult,' says Professor Tipu Aziz, a consultant neurosurgeon at the John Radcliffe Hospital in Oxford and one the UK's leading exponents of DBS.
'The technique was attempted on a patient in Canada and it failed. They found it helped his depression, but did not affect his desire to eat.'
Yet some British experts believe that medically, this approach makes sense.
As Dr Ian Campbell, of the medical charity Weight Concern, says: 'We know that hormones and the hypothalamus play a role in controlling appetite and so it would be logical to use the brain as a way of treating obesity.
'Up to a third of gastric surgery procedures fail for a variety of reasons and patients do not lose a sufficient amount of weight.
'Obesity is a disease that kills and we need to be looking constantly for new ways of treating it.
'There is no one way that works for everyone and so we need a variety of options. If the trials in the U.S. prove deep brain stimulation safe and effective, I would not have a problem supporting it.
'It sounds radical, but I recall people saying that gastric bypass surgery was radical and dramatic when it was first introduced. People questioned whether you should use surgery to treat obesity. Now no one gives it a second thought.'
Dr Whiting believes the results from his first two patients more than justify treating more patients with deep brain stimulation.
'We still need to do a lot of fine-tuning, but we seem to be moving in the right direction with their weight loss. Also, the trial has official approval, which wouldn't have been granted if there were serious questions over whether it might not work.
'Ultimately, we hope that if the trial is successful, surgeons in other countries will start performing the operation.'
Meanwhile, he says there is no shortage of obese patients willing to volunteer for the trial, with six more of the operations scheduled in the near future.