Running may produce more dramatic weight loss results than walking, according to research to be published in the April edition of Medicine & Science in Sports & Exercise - the official journal of the American College of Sports Medicine.

The six-year study conducted an analysis of body mass index change (BMI) of 15,237 walkers and 32,216 runners, under non-experimental conditions.

Primary investigator Paul T. Williams said: "After studying groups of people who had adopted a regular walking or running programme, both groups lost weight, but the runners lost significantly more.

He said in those with a BMI over 28, running produced 90 per cent greater weight loss than walking when done in the same amount.

Williams said: "Many clinical trials seem to suggest that moderate and vigorous activity produce equivalent loss of total weight and abdominal fat, but our results indicate that high-intensity exercise can indeed produce greater results."

Because the participants in the study were volunteers it was recognised they tended to be healthier than the general population and further research would be needed to see if these results could be replicated in a controlled clinical trial.