NASHVILLE - Summer vacation can be a tough time for kids who don't have summer classes to attend, or an organized reading program.

They can lose part of what they've learned - and they may also gain weight, Jeff Smink with the National Summer Learning Program warns.

"Kids lose academic skills over the summer months, particularly in reading. There's also an emerging body of research showing that kids actually gain weight over the summer, at rates much faster than during the school year."

Often, children of pre-kindergarten age are better off, because of federal and state-subsidized year-round programs such as Head Start. Smink says parents of K-through-12 kids should check with schools, libraries, and parks and recreation department officials to find out what's available to them. He says if there are no affordable programs, even working parents should try to find an hour a day, at the very least, to read with their kids.

Smink says research shows the value of an engaging summer reading program - as well as the cost of not having access to one.

"Typically, it shows that kids - in particular, low-income children - fall two to three months behind in reading, whereas a high-quality program can actually create gains in reading over the summer."

Some migh think that kids would be more active in the summer, when they're not sitting in a classroom much of the day, but Smink says that's often not the case.

"Not having the structure that's associated with the school day leads to more snacking, things like that. We also know that kids in high-poverty communities often live in neighborhoods where it's not safe to go outside, so they're actually inside more and less active."

He says the best summer programs avoid the stigma of "summer school" by incorporating field trips and fun activities, along with the structure and academic work that keeps kids from summertime back-sliding.