Many behavioral risk factors, such as smoking, drinking and obesity, cause chronic health conditions, which in turn, drive up health care costs. Although much research has been conducted on behavioral risks like drinking and smoking, only recently have public health advocates began to focus attention on the health care costs of being over-weight. Furthermore, the problem is more widespread than previously thought. For example, one survey found 36 percent of the population is overweight, and approximately two-thirds of the overweight are obese. However, when surveyed, people often under-report weight and over-report height.

Measuring weight using the body-mass index -- which is calculated by weight in kilograms divided by height in meters squared -- researchers find:

• Being overweight (BMI of 25-29.9) increases yearly health care costs by $125, while obesity (BMI of 30 and above) is associated with an average increase of $395 per year.

• The cost of smoking ($230) is far lower, while problem drinking adds $150 in additional health care spending.

• Aging accounts for $225 (annually) in additional health care spending per person.