We all know that obesity causes lots of health problems and, as a result, has substantial economic repercussions. Now a new study by the Society of Actuaries has put an eye-popping priced tag on the cost of overweight and obesity in the US and Canada. It's $300 billion a year, 90 percent of that in the US.

The study defines being overweight as having a BMI of between 25.0 and 29.9 and obesity as a BMI of more than 30. And it breaks down the economic costs according to specific causes. For example, the total cost of excess medical care is $127 billion; for economic loss of productivity caused by disability for active workers, it's $43 billion, and productivity loss from "excess mortality", $49 billion.