Videogames were once blamed for rising obesity rates but are now being championed by the medical industry and for use by government departments for their health benefits.

Games like Electronic Arts' EA Sports Active and Nintendo's Wii Fit have got players of all ages moving -- and game developers and investors looking for hot new titles to cash in on this booming segment of the market.

Big John Games' upcoming Butt Kicker Nintendo DSi game will provide an action-based environment in which players fight against cigarettes and Karate Bears for Wii teaches players real karate routines using the Wii's motion-sensor controllers.

With interest in health games rising, the fifth annual Games for Health Conference in Boston expanded to 390 people this year from 100, including developers, investors and medical experts, while numbers at many other conferences are down up to 40 percent.

Healthcare is 18 percent of the GDP of the United States and so games for health is probably the largest sector of activity in the serious games field long-term, said Ben Sawyer, co-founder of The Games for Health Project.

If you add up the 18 month sales of Wii Fit and the sales of EA Sports Active, Konami's Dance Dance Revolution and other healthy games, the worldwide retail numbers are over $2 billion.

Dr. Michael Levine, executive director of the Joan Ganz Cooney Center at Sesame Workshop which fosters innovation in children's learning, has just released a report looking at how digital games can play a beneficial and educational role in health care.

The White House should launch a national initiative to promote research and development of proven games, said Levine.

The Robert Wood Johnson Foundation, whose mission is to improve the health and healthcare of all Americans, has also called for a public engagement campaign supported by the president, Congress and the federal agencies to teach parents, teachers and health providers about the healthy side of gaming.

States' governors should direct their school technology officers to look at innovations like Dance Dance Revolution and Wii Fit as a way to extend the reach of physical education and comprehensive health education, said Dr. Debra Lieberman, director of Health Games Research for the foundation.

The Games for Health Conference also showcased how videogames are being used to help doctors and patients alike.

Serious games developer Virtual Heroes is working on a new first-person shooter sequel for Hope Lab's popular Re-Mission game, which has been distributed to cancer patients in 81 countries since 2006.

We're taking their existing concept and trying to raise the fun bar and creating more lifelike and enjoyable environments within the human body, explained Jerry Heneghan, CEO of Virtual Heroes.

Players will take control of Roxy, the protagonist, and have new weapons to battle cancer with thanks to input from cancer patients.

Virtual Heroes is also updating its HumanSim technology with a new human physiology engine, technology has been used by Duke Medical Center's nursing school to train nurses virtually.

Heneghan said he hopes this software will inspire gamers to turn to careers in healthcare and make people in the medical profession more proficient with more grants and funding flowing into universities for health games.

(Editing by Belinda Goldsmith)