Excess body fat causes an estimated 100,500 U.S. cancer cases every year, an analysis by a large U.S. cancer research organization indicated Thursday.

The American Institute for Cancer Research analysis, based on updated cancer data and a report released this year by a panel of experts, also indicated only half of Americans realize that carrying excess body fat places them at significantly higher risk for cancer, the nation's No. 1 health concern.

"In light of the fact that excess body fat causes over 100,000 cancer cases each year in the U.S. -- cases that could be prevented by staying lean -- public awareness of the link remains alarmingly low," institute Nutrition Communications Manager Alice Bender said at a Washington news conference. "It's a message that desperately needs to be heard."

Among the types of cancer most strongly linked to excess body fat are breast cancer, with 33,000 cases a year caused by obesity; endometrium (the inner membrane of the uterus), with 20,700 cases a year; kidney, with 13,900 cases; colon, 13,200; pancreas, 11,900; esophagus, 5,800; and gallbladder, 2,000.

The institute's analysis comes on the heels of new estimates that obesity-related diseases add $147 billion to the nation's healthcare bill. About a third of U.S. adults are obese, or roughly 30 or more pounds above a healthy weight.

Obesity also increases the risk of diabetes, heart disease and other diseases.