In Texas schools, a picture's worth 1000 calories

SAY CHEESE: Children's eating habits are under scruitiny in US schools.
SAY CHEESE: Children's eating habits are under scruitiny in US schools.

Smile, schoolchildren. You're on calorie camera.

Health officials trying to reduce obesity and improve eating habits at five elementary schools in Texas have unveiled a $US2 million research project that will photograph students' lunch trays before they sit down to eat and later take a snapshot of the leftovers.

A computer program then analyses the photos to identify every piece of food on the plate - right down to how many ounces are left in that lump of mashed potatoes - and calculates the number of calories each student scarfed down.

The project, funded by a US Department of Agriculture grant, is the first of its kind. The cameras, about the size of pocket flashlights, point only toward the trays and don't photograph the students. Researchers say about 90 per cent of parents gave permission to record every morsel of food their child eats.

"We're trying to be as passive as possible. The kids know they're being monitored," said Dr Roger Echon, who works for the San Antonio-based Social & Health Research Center.

Here's how it works: Each lunch tray gets a barcode sticker to identify a student. After the children load up their plates down the line - coleslaw or green beans? french fries or fruit? - a camera above the cashier takes a picture of each tray.

When lunch is over and the plates are returned to the kitchen, another camera takes a snapshot of what's left. Echon's program then analyses the before and after photos to calculate calories consumed and the values of 128 other nutrients. It identifies foods by measuring size, shape, colour and density.

Parents will receive the data for their children, and researchers hope eating habits at home will change once parents see what their kids are choosing in school. The data will also be used to study what foods children are likely to choose and how much they're eating.

Nine-year-old Aaliyah Haley went through the lunch line at WW White Elementary with cheesy enchiladas, Spanish rice, fat-free chocolate milk and an apple. Two cameras, one pointed directly down and another about tray-level, photographed her food before she sat down to eat.

"I liked it. It's good food that was good for me," Haley said.

Just how healthy it was researchers don't know yet. Echon is still developing the program and expects to spend the first year of the four-year grant fine-tuning the equipment. By the 2012-13 school year, the Social Health & Research Center plans to have a prototype in place.

Echon has already made some changes to the project. It learned that mashed potatoes served on some campuses are lumpier than those served on others. The programme now accounts for consistencies and texture.

The database already includes about 7,500 different varieties of food. Echon said he started from scratch because there was no other food-recognition software to build upon. He insisted on creating technology to record meals because asking eight-year-olds to remember what they ate and write it down is seldom accurate.

Researchers selected poor, minority schools where obesity rates and diabetes risk are higher. Among those is White Elementary, which is just off a busy interstate highway on the city's poor east side, on a street dotted with fast-food restaurants and taquerias.

In Bexar County, where the five pilot schools are located, 33 percent of children living in poverty are obese.

Researchers warn that obesity is not always the result of children eating too many calories. A previous study by the non-profit center reported that 44 per cent of children studied consumed calories below daily minimum requirements, but nearly one-third were still obese. Seven per cent screened positive for type 2 diabetes.

Mark Davis, the school's principal, said getting consent from parents hasn't been a problem. He suspects the small number of parents who withhold consent don't understand the project, perhaps thinking it limits what their child can eat at school.

"Nothing in the program says they can't have something," Davis said. "It just says we're tracking what it is."