Overweight Canadians are more likely to miss work or be unproductive at the office, and they report higher job stress and less support from their co-workers and bosses.

That's according to a new Statistics Canada report that also shows increasing numbers of people falling into this category, with obesity rates in the Canadian workforce rising to 16 per cent in 2005 from 13 per cent a decade earlier. The rate is rising fastest among men, Statistics Canada says, and obesity is most common among older workers aged 55 to 64.

The trend may come from an environment that "encourages excessive eating and discourages physical activity and to increases in more sedentary jobs," the agency notes.

"Obesity really is a societal problem," said Dr. Arya M. Sharma, scientific director of the Canadian Obesity Network. "We've virtually eliminated physical activity from the workplace . . . We have to make up the lost physical activity in our spare time."

Obese men under age 35 are almost four times more likely to miss work than those of normal weight, the agency found. However, "presenteeism" or reduced productivity on the job may be the bigger problem for overweight workers and their employers, it says.

"None of this is surprising," said Dr. Yoni Freedhoff, medical director at the Bariatric Medical Institute in Ottawa.

Bariatric medicine concerns the treatment of obesity and associated conditions.

"Weight contributes to a lot of morbidity," Freedhoff said, adding that illness and injury can cause absence from work, while co-morbid conditions such as sleep apnea result in lost productivity.

Overweight people are also likely to retire earlier, and to draw lower salaries while on the job, leading to lost tax revenue, Freedhoff said.

More obese workers also report high job stress and low support from those they work with than their thinner counterparts, Statistics Canada found, but it's difficult to unravel which came first.

The report says that while "higher job stress may precede obesity," being obese in the workplace may also lead to stress.

"There's increased bullying of obese people. They're less likely to be promoted. They're less likely to be hired in the first place," Sharma said.

Men aged 35 to 54 in the bottom half of the earnings ladder are less likely to be obese than those in the top quarter, but women aged 18 to 54 with low income are more likely to be obese than high earners.

While StatsCan suggests that this may be due to different "symbolic values of body size" for men and women, or to the fact that higher-earning men are more likely to dine out on rich foods, Freedhoff said that no one knows for sure why this relationship exists.

In Sharma's opinion, the trend towards obesity in the workplace is unlikely to improve. The economic downturn, he said, will create stress for both employed and unemployed people, leading to an increase in stress-related eating. People are also less likely to eat healthy food, he said, and will cut back expenditures, such as sports and gym fees.

The report also found that factors such as level of education, type of work and work hours affected the likelihood of obesity.

Marital status also plays a role, with never-married workers under age 35 less likely to be obese than their married colleagues, the report finds.

And many more Canadian workers are overweight than are willing to admit it. Based on self-reported height and weight, 59 per cent of working Canadian men were obese or overweight in 2005, but actual body measurements from the year before put that figure at 63 per cent.

For women, the contrast is even more stark: 39 per cent of employed women aged 18 to 64 were considered overweight or obese, but measurements from 2004 show that 50 per cent actually fell into that category. The "stigma" surrounding obesity may motivate people to lowball their weight, Statistics Canada says — especially for women.