Need to lose a few pounds but just can't seem to do it? perhaps a day off with full pay for losing some weight might be the incentive you need. Government Employes Insurance Co. offers its employes just such a deal in the hope that, by encouraging their good health, the company will reduce the cost of its employe health benefits program.

Unlike some big national companies, which had begun innovative programs to try to hold down rising health costs, most firms in the Washington area are too small to have such programs. Geico, however, does have a new program.

Geico employes participating voluntarily in a special program earn a day off with pay if they don't gain weight during a six-month period. As an added incentive, the company is giving away tickets to Washington Redskins professional football games to the employe who loses the greatest percentage of his body weight during a specified time period, explained Bob Jackson, director of public relations.

Xerox Corp. is another firm in the Washington area that is trying new ways to reduce health care costs.At Xerox's management training center near Leesburg, the company has invested $3.5 million in a fitness and recreation center that features a country-club assortment of squash courts, weight room, indoor track, tennis courts and the like.It is used by Xerox personnel who come from all over the country to receive sales or service training at the Leesburg facility.

Xerox built the fitness center as a place for employes to release stress and to keep themselves physically fit, Brent Arnold, manager of the center, said.

"We believe a physically fit employe is a mentally fit, productive employe," Arnold said. "Xerox has found that an increase in fitness means a decrease in absenteeism and employe turnover, and an increase in morale, productivity and efficiency."

Arnold said the centeer is designed to provide employes new, physically taxing leisure time activities that they can learn and continue at home, as well as instill in them a desire to stay in shape. Arnold said he soon will begin a new program to encourage more Xerox emplyes to use the fitness center.Now, about 10 percent of the training center employes use the fitness center, he said, while an even smaller percentage of the students in training use it.

Geico's and Xerox's programs to promote their employes' good health reflect a growing concern among U.S. businesses about rising health costs, which raise the costs of the health benefits programs companies provide their employes. The average firm faces an annual increase of 10 to 12 percent in its health costs, one economist has estimated. While large national companies can afford to devote money and manpower to trying new ways of keeping those health costs down, smaller firms, like most of the Washington area businesses, cannot.

Small companies "don't have people employed to do a lot in the benefits area," explained Willis Goldbeck, executive director of the Washington Business Group on Health, a research and lobbying group that that concentrates on health issues affecting industry. For the small firm, the person in charge of the benefits program often handles a dozen other areas of the business, he said.

Generally, small companies don't have the clout that larger firms have to push around an insurance company or a hospital, he said.

The concern to hold down health costs lies not just with business, but also with unions who offer benefits programs to their members. One benefits program for about 22,000 grocery store clerks in Washington and Baltimore has insitituted several new programs. It now requires employes to get the opinion of a second doctor before being admitted for nonemergency surgery, which the benefits program administrator, Arthur Chambers, hopes will prevent surgery that really wasn't necessary.

Chambers said the benefits program also operates a multifacet screening program from a trailer that travels to grocery stores represented by the Food Employers Labor Relations Association and Retail Employers Union Health and Welfare Fund, for which he administers the benefits program. The screening program, which is a series of tests of blood, hearing, vision and other areas, is designed to catch health problems before they become serious, he said.

While other large Washington firms say they are not making nay major changes in their health benefits programs, they say they are beginning to watch more closely the rising costs of those programs. For instance, one company has hired an outside firm to audit its benefits program and suggest cost control measures.