A shortage of research funds is crippling attempts to find a cure for obesity, a leading scientist said yesterday.

Steve Bloom, a professor at Imperial College and Hammersmith hospital in London, said attempts to find drugs that could tackle the problem had been "a failure" with only two out of 114 brought to market having even a "weak" impact.

Government, other funding bodies and promoters of fashionable diets, all bore responsibility, he said. Only about 10 diets had been properly researched and studied in the past 50 years.

The field was "still like the middle ages as far as science is concerned" because obesity was regarded as a moral problem and could be solved by people just eating less.

"The scientific funding industry has failed to fund obesity," Prof Bloom said. "It is just like any other science and it needs to be funded."

His research involves developing a natural hormone, PYY, into a hunger-regulating treatment.