Washington ? At most restaurants, customers are left to guess how many calories they’re consuming. The government soon may try to change that by requiring or encouraging restaurants to display calories on their menus alongside the salads, entrees and desserts.

The Food and Drug Administration said Thursday that labeling menus was among several proposals it was considering to help people watch what they eat.

Food companies already are required to put nutrition information on the backs of food packages, and nutrition advocates have been pressuring the government and the industry to impose similar requirements on the restaurant industry.

The FDA also may change its requirements for nutrition labels on food sold in grocery stores and other outlets.

Joseph Levitt, vice chairman of an FDA committee studying obesity, said FDA officials were meeting with the restaurant industry, food processors and consumer groups to figure out whether it should issue new regulations or just write guidelines suggesting changes to help consumers improve their eating habits.

“It’s not precisely clear at FDA what our role should be,” he said.

Allison Whitesides, director of legislative affairs for the National Restaurant Assn., said the industry group opposed mandatory labels on menus. It would be especially cumbersome for restaurants that serve different meals each day, she said.

“We’re not a box, we’re not a can,” Whitesides said. “Cooking is an art. It’s not an exact science.”

But, she said, the industry might consider a voluntary program. She noted some fast-food chains, including McDonald’s, already display calorie information in their stores or on their Web sites.

The Centers for Disease Control and Prevention regards fat as a leading health problem, estimating that 15 percent of children and 65 percent of all adults are overweight. A recent spate of lawsuits has food companies and restaurants fearful they may be blamed for it.

The FDA says it will release a plan to fight obesity in February.