School nutrition advocates say that for students to eat more healthfully--more salads, fruits and vegetables--schools must provide them with more time to eat. The Center for Investigative Reporting says that school and health organizations recommend that students have at least 20 minutes to eat lunch after they’re served. But that’s not happening in all schools, according to the School Nutrition Association. Nationwide, the average lunch period was 31 minutes in 2009-10, according to the U.S. Department of Agriculture’s most recent data. Students waited in line an average of five minutes and as long as 30 minutes to get lunch, food service managers reported. The Los Angeles Unified School District has had a 20-minute standard since 1990, but last year, a district analysis showed that seven out of 10 high schools and nearly half of elementary schools missed the mark. When students don’t have the time, they often choose to forgo school lunch.