If you think that eating too much or exercising to little are the only factors that are involved in gaining weight, researchers say you may be overlooking an important factor – your job. 

More than 1.9 billion adults worldwide are overweight and, of these, more than 600 million are obese. Because of the rise in obesity, researchers are interested in rooting out all the factors that can lead to weight gain.

Researchers in Australia looked at data from a prior study involving 450 mostly middle-aged participants (230 women, 220 men), who worked in a variety of different occupations, both blue and white-collar.

They measured participants' height, weight and waist circumference in a clinic and conducted telephone interviews to collect information about their work. Then they assessed the psychosocial qualities of their work.

Traditionally, high job demands are considered stressful, while high job control has been considered useful in mitigating this. However, skill discretion and decision authority are usually assessed together. In the new study, the team took these two factors separately.

They found that having skills and the freedom to use them at work was linked to lower BMI and smaller waist size, whereas needing to make a lot of decisions was linked to bigger waist size.

The study appears in the journal Social Science & Medicine.