An effective way to lose weight is to keep physically active. A new research suggests that people can shed off more pounds if they start walking instead of using cars to travel short distances.

Researchers from University of Illinois found that driving may be contributing to the obesity trend in the U.S. According to them, even small reduction in driving and calorie intake by people can lead to significant weight reduction.

Spending less time in the car may be an easy way to remain active, says Sheldon H. Jacobson, the study leader and a professor of computer science and mathematics.

"We're saying that making small changes in travel or diet choices may lead to comparable obesity reduction, which implies that travel-based interventions may be as effective as dietary interventions," said graduate student Banafsheh Behzad, a co-author of the study.

For the study, researchers used data that was publicly available on national average BMI, driving habits and calorie intake of people. They developed a multivariable model that showed how intake of calories and driving correlated with BMI.

The model predicted that, if all adults in the U.S. drove 1 mile less per day then we could see a decrease in the national average BMI by 0.21 kg/m2 after six years while if all people just cut down 100 calories from their diets, the average national BMI would be reduced by 0.16 kg/m2 after three years.

Behzad added that if people considered taking the bus, then walking down to the bus-stop could be like eating 100 calories less a day.

"The most important thing for people to learn from this study is that they have a choice. One has to be just as careful about when you choose to drive as when you choose to eat. These small changes in our driving and dietary habits can lead to long-term significant changes in obesity issues. Those are the kind of changes we advocate," said Jacobson.

The study is published in the journal Preventive Medicine.