Middle-aged women who spend long hours working are more at risk of gaining weight, according to a new study.

Published in the International Journal of Obesity, the study analysed the impact of employment status and the number of hours worked on the weight of middle-aged women and found those who worked in excess of 35 hours were more likely to experience weight gain.

Researchers led by Dr Nicole Au, from the Centre for Health Economics at Monash University, analysed 9276 women aged 45–50 years using the Australian Longitudinal Study of Women’s Health for 1996 and 1998. The study found 55 per cent of the women gained weight over the two-year period. On average the women gained 1.5 per cent of their initial weight while extreme amounts of weight gain were also evident.

Dr Au attributed longer working hours to increased weight gain with women spending less time maintaining their health and fitness levels.

“More than 60 per cent of Australian adults are now overweight or obese, representing a serious public health concern,” Dr Au said.

“The study highlights the growing number of Australian women entering the workforce and the effects on their ability to maintain a healthy weight. Extended work hours may reduce the time spent preparing home-cooked meals, exercising and sleeping which are risk factors for obesity.

“Policies that assist women who work long hours to reduce the time costs of sustaining a healthy diet and their physical activity routine may have positive benefits.”

Women working more than 49 hours were more likely to smoke and consume alcohol with 65 per cent drinking at risky levels and 36 per cent did not engage in any physical activity.