Commuters can make a significant difference to their weight and health by leaving the car at home, according to new research.
A study of more than 150,000 British individuals aged 40 to 69 found that those who walk, cycle, or even take public transport to work have less body fat and a lower BMI (Body Mass Index) than motorists.
The greatest gains were seen in cyclists. For the average man aged 53, cycling to work instead of driving was associated with a weight difference of 5kg (11lbs).
The average 52-year-old woman cyclist was 4.4kg (9.7lbs) better off than her car-driving counterpart.
BMI, a measure that relates weight and height, was 1.71 kg/m2 lower for men who cycled and 1.65 kg/m2 lower for women.
Cycling and walking also reduced the body fat of men and women, by 2.75% and 3.26% respectively.
Lead scientist Dr Ellen Flint, from the London School of Hygiene & Tropical Medicine, said: "We found that, compared with commuting by car, public transport, walking and cycling or a mix of all three are associated with reductions in body mass and body fat percentage, even when accounting for demographic and socio-economic factors.
"Many people live too far from their workplace for walking or cycling to be feasible, but even the incidental physical activity involved in public transport can have an important effect."
Findings from the study, funded by the Medical Research Council, appear in The Lancet Diabetes & Endocrinology journal.
An estimated 23.7 million people in England and Wales regularly commute to work and 67% travel by car.
Among the study participants, 64% of men and 61% of women drove to work, while 4% of men and 2% of women cycled or combined cycling and walking.
The scientists analysed data stored on the UK Biobank, which holds health-related information on 500,000 anonymous individuals.
Dr Flint added: "Physical inactivity is one of the leading causes of ill-health and premature mortality.
"In England, two-thirds of adults do not meet recommended levels of physical activity.
"Encouraging public transport and active commuting, especially for those in mid-life when obesity becomes an increasing problem, could be an important part of the global policy response to population-level obesity prevention."
In a linked comment published by the journal, Dr Lars Bo Andersen, from Sogndal and Fjordane University College, in Sogndal, Norway, said: "The finding of a positive effect from active commuting is important, because commuting to work is an everyday activity that lots of working people need to do.
"Physical activity during commuting has health benefits even if its intensity is moderate and the commuting does not cause high heart rate and sweating."