A starving economy is padding the world’s obesity rate, according to a new report.

The study, published Tuesday by The Organization for Economic Co-operation and Development, looked at the "obesity epidemic" in 34 countries, finding the global average of obese adults to be nearly one in five (18%).

That shows rates have nearly doubled since 1980, when fewer than 1 in 10 people in OECD countries were obese.

In Canada, it found that more than half the population is now overweight, with one out of four considered obese.

The 2008 recession caused families to cut their food expenditures, the OECD says. Perhaps counterintuitively, the decrease in spending led to an increase in calorie intake.

"Tighter food budgets have provided incentives for consumers to switch to lower-priced and less healthy foods," reads the report.

"The evidence of a possible impact of the economic crisis on obesity points rather consistently to a likely increase in body weight and obesity."

It’s simple to explain, says David Lau, an obesity expert from the University of Calgary.

"If we hit a financial crisis where money is tight, people tend to eat less fruit and vegetables because they’re the more expensive and perishable items that people can avoid," he told CTV News Channel.

He added that fast food restaurants offer cheap food that doesn’t need to be prepared, which is appealing to those stressed out and looking for work.

"You can feed a family of four in Canada for less than $15," he says. "Where else can you buy food for that little money?"

Obesity rates in Canada have been slowly climbing since the 1990s, and the country ranks sixth among OECD member countries in terms of obesity. Only the U.S., Mexico, New Zealand, Hungary and Australia have a higher percentage of obese adults.

But while Canada sits near the top of the charts, the OECD pointed out that the growth rate of obesity here is at least slowing.

"Obesity rates are high in Canada, relative to most OECD countries," it says. "But they have not increased substantially in the last 15 years."

The report also shows a correlation between education level and obesity rates in most countries, including Canada.

Those with "low education" are almost 1.5 times more likely to be obese than their "high education" counterparts, it says.

Canadian children were tipping the scales a little less than adults – but not by much. About 25 per cent of those under 15 in Canada are considered “overweight,” a few percentage points above the OECD global averages for boys (23%) and girls (21%).

The OECD study also looks at a variety of prevention programs, including school-based intervention and improving food labelling. Better counselling by a family physician was the most effective way to improve health, it concluded, stating up to 40,000 "life years in good health" could be gained across Canada annually.

The think-tank also thinks the cost of the prevention programs will eventually balance out against the strain obesity puts on the health care system.

"In Canada, all of the prevention programs examined will be cost-effective in the long run," the report states.