People who switched from driving to work to using public transport, cycling or walking lost significant amounts of weight, a study has found.
Research led by the University of East Anglia in the UK had 4,000 participants describe their main mode of transport for their daily commute and provide details of their height and weight, which was used to calculate their body mass index (BMI).
Researchers then used a series of analyses to see if changes in mode of transport were linked to changes in weight over a two-year period.
In the first part of the study, which included 3,269 respondents, 179 people had stopped driving to work and were either walking or cycling or taking public transport.
Switching from a car to walking, cycling, or using public transport was associated with an average reduction in BMI of 0.32kg/m2 - equivalent to a difference of around one kilogram a person.
The longer the commute, the stronger the association, with a weight loss of around 2kg associated with journeys of more than 10 minutes, and 7kg on average for journeys of more than 30 minutes.
In the second analysis, which included 787 people, 268 switched from active to passive travel.
Some 156 stopped walking or cycling and 112 switched from public transport (usually a bus or coach) to the car.
Switching to a car was associated with a significant weight gain of around 1kg per person after taking account of other influential factors.
"Combined with other potential health, economic and environmental benefits associated with walking, cycling and public transport, these findings add to the case for interventions to promote the uptake of these more sustainable forms of transport," the authors concluded.