Late last year the Global Observatory for Physical Activity (GoPA), a council of the International Society of Physical Activity and Health (ISPAH), released its first Physical Activity Almanac. The document summarizes physical activity indicators including surveillance, policy, research, and deaths due to physical inactivity through a set of 139 graphical Country Cards. The full document can be accessed here.
According to this data, in USA 10.8% of all deaths are due to inactivity.
The Centers of Disease Control and Prevention provide complementary data:
More than one-third (36.5%) of U.S. adults have obesity. [Read CDC National Center for Health Statistics (NCHS) data brief PDF-704KB]
Obesity-related conditions include heart disease, stroke, type 2 diabetes and certain types of cancer, some of the leading causes of preventable death. [Read guidelines]
The estimated annual medical cost of obesity in the U.S. was $147 billion in 2008 U.S. dollars; the medical costs for people who are obese were $1,429 higher than those of normal weight.