Food supplements which trick the body into thinking the stomach is full could combat Britain's spiraling obesity crisis.
Scientists in London believe capsules could replicate the effects of gastric bypass surgery, by telling the body it is satisfied.
They hope the treatment, which could be available on the NHS in the next five years, could save thousands of people going through the irreversible operation.
The breakthrough could pave the way for revolutionary new treatment for obesity and type 2 diabetes, predict the researchers, from Barts and the London School of Medicine and Dentistry, Queen Mary University of London.
The study, funded by the charity Bowel and Cancer Research and the Wellcome Trust, discovered the lower intestine could be targeted by special food supplements which trick the body in to thinking the stomach is full.
Lead researcher Professor Ashley Blackshaw, said the difference between obese and lean people is that overweight people ignore the signals from the small intestine telling the brain the body is full.
He said: "At the moment, obese patients undergo gastric bypass surgery where they are essentially re-plumbed - undigested food bypasses the small intestine and is shunted straight to the lower bowel where it causes the release of hormones which suppress the appetite and help with the release of insulin.
"That makes the patient feel full and stops even the hungriest individual from eating.
"We believe it's possible to trick the digestive system into behaving as if a bypass has taken place by administering specific food supplements which release strong stimuli in the same area of the lower bowel.
"It's a bit like sending a special food parcel straight to the body's emergency exit, and when it gets there, all the alarms go off."
Bypass surgery is currently among the most effective treatment for obesity and type 2 diabetes.
The procedure is known to improve blood sugar levels and help patients lose weight quickly.
The National Institute of Health and Care Excellence (Nice) has just produced new draft guidelines suggesting its use could be expanded in the NHS to tackle an epidemic of type 2 diabetes.
But surgical treatments have drawbacks, including irreversibility and cost.
"What we are doing is targeting the area of the gut where that sense of feeling full begins with a capsule containing naturally occurring food supplements," said Professor Blackshaw.
"By refining those high-energy supplements and formulating them to target the lower bowel, we expect to develop a successful weight loss and anti-diabetic strategy before, and possibly in place of, bypass surgery.
"We are pursuing the opportunity to intervene directly with fatty acid, amino acid and protein sensing pathways of the lower bowel to modify endocrine responses.
"It's a totally novel idea, and we're very excited at the results so far. We are hopeful that the treatment will be widely available in NHS hospitals in the next five years."
He added that the only predicted side-effect is nausea which could be easily controlled.
Experiments were carried out on human tissue at the National Centre for Bowel Research and Surgical Innovation in Whitechapel. The next step is to find funding for substantial clinical trials.
Gastric bypass surgery is irreversible and patients have to take supplements for the rest of their lives.
Deborah Gilbert, Chief Executive of Bowel & Cancer Research, hailed the new research as a significant step.
She said: "We are delighted that such a significant piece of work has been supported with our funding.
"This is leading edge science, and as a result it can be difficult to find the financial support to push boundaries in this way.
"Not only could Professor Blackshaw's work have a major impact on the growing problem of obesity and type 2 diabetes, but with the link with weight and bowel cancer clearly established, it could have even wider implications."
The study was published in GUT, the international journal of gastroenterology and hepatology.
Obesity crisis sparks 30-fold rise in bariatric surgery
There has been a marked increase in obesity in the UK. In 1993, 15 per cent of the population were obese. In 2011, levels rose to 25 per cent.
At the same time, weight-loss surgery has increased 30-fold in the last decade. More than 8,000 operations take place annually on the NHS, and many more through private clinics.
Also called bariatric surgery, it is used as a last resort to treat people who are dangerously overweight.
It is only available on the NHS to treat people when all other treatment, including lifestyle changes, have not worked.
Privately the a gastric band operation costs between £5,000 (NZ$9860) and £8,000 (NZ$15,780), while gastric bypass surgery costs up to £15,000 (NZ$29,590).