Stressed parents are skimping on healthy food and regular exercise as they attempt to reconcile long working hours and family responsibilities, according to a report published today.

A study by Working Families, a campaign group for parents and carers, suggests that "binge working" is having a "disastrous" effect on health, family life and performance at work. Half of the parents surveyed for the report, Time, Health and the Family: What Working Families Want, were unhappy with their work and family balance. A majority reported that work dominated their lives and therefore family life suffered.

Working long hours led to increased levels of stress, causing irritability, exhaustion and depression.

Parents also admitted to cutting back on exercise because of the time spent at work, with a quarter of those working more than 45 hours a week saying the problem affected them all the time.

More than a third of the 646 parents interviewed also said they often, or always, relied on convenience meals, and the same proportion reported turning to convenience foods.

Despite government moves to offer parents of children up to the age of five the right to ask to work flexibly, nearly half of those interviewed had no flexible working arrangements available in their workplace. A majority of all parents thought they themselves should take responsibility for improving their work-life balance and the solution was to look for another job rather than press for flexible arrangements.

Research elsewhere shows this trend affecting women in particular, who commonly "downgrade" to a lower status, lower paid, part time job after having children to fulfill their caring responsibilities.

Sarah Jackson, chief executive of Working Families, said: "This disturbing report shows us that binge working is turning us into a nation of workaholics. This is having a disastrous effect on our health, our family life and our performance at work. We need to work shorter, leaner hours and make time for our families and communities."

The report's co-author, Cary L Cooper, a professor at Lancaster University, said: "The clear message to employers from this research is that 'time is up on long hours working'. They need to look closely at the culture in their organisations or risk losing the parents who work for them. Far from leading to an effective workforce, working long hours leads to high levels of stress, ill health and decreased morale and productivity.

"Merely having flexible working policies is not sufficient if the dominant culture does not support their meaningful use. It's time to work smarter, not longer."