Computerised nags are ringing overweight patients and telling them to eat less and get more exercise.
The Center for the Advancement of Health in Washington DC, said that more than 300 human guinea pigs responded well to a PC which has a pop at them about their weight and fitness.
Doctors wanted the patients to exercise and eat more healthily, but discovered that they did not like a human telling them this and responded better to a computer.
Lead researcher Bernardine Pinto explained that the machines were accessible at any time, and less likely to be perceived as judgmental.
The system quizzes patients about their habits, who reply by pressing a number on their phone.
Having assessed their motivation, or lack of it, the computer suggests a task or goal and rings the patient at set times to check on their compliance.
After three months, more than a quarter of the participants had achieved the recommended levels of exercise, compared to fewer than one in five of a group with a human advisor.
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