[Image: photographing meal]
News Release Distributed 01/10/14
BATON ROUGE, La. – Keeping track of one's diet doesn't have to be boring. With the help of camera-enabled smartphones, visual food diaries are easy to create and more effective for nutrition researchers.
The LSU AgCenter and Pennington Biomedical Research Center began a joint study of remote food photography in 2012. Participants used smartphones to photograph each meal they consumed in a three-day period. The photos were sent to a custom-built server at Pennington, where dietitians compared them to images of certain portion sizes and components.
Georgianna Tuuri, an associate professor in the LSU AgCenter's School of Nutrition and Food Sciences, said the goal was to compare how much energy and how often people of different ages eat. Pennington gathered data from adults, while the AgCenter worked with a group of about 20 high schoolers at University High School on LSU's campus.
Popular belief suggests young people snack more often, but the study found the opposite was true, with some adult participants eating as often as 10 times per day, Tuuri said. Young people are constrained by class schedules at school, she explained, causing them to eat fewer but more energy-dense meals.
There is always human error in reporting dietary information, whether using photos or traditional methods such as food diaries or interviewing participants about what they ate. Tuuri pointed out that "there is no good way to collect dietary information" because people sometimes forget or choose not to report certain foods they eat. It is also difficult to analyze ingredients such as salt, which some people are not sure how to record in a diary and cannot be seen in photos.
Smartphone photos do have advantages, however, in that they conveniently and precisely document exactly what people eat and how often, Tuuri said. Remote food photography harnesses popular technology to more accurately investigate eating patterns and nutrition as well as minimize problems researchers and participants have with paper documentation.
Another benefit is being able to communicate with study subjects in real time, allowing researchers to catch errors or ambiguities that may skew data.
"If the dietitian looks at the pictures and sees a glass of milk, and she doesn't know what kind of milk, she can text them and say, 'What kind of milk was that?'" Tuuri said.
Smartphones also enable people to make better decisions about food on the go. For example, someone dining at Subway could use mobile Internet to quickly determine how many calories in a sandwich, Tuuri said.
Now that researchers have accumulated a library of food photos, Pennington is working to automate the process of comparing participant and database photos. Tuuri said this could cut costs in future studies because dietitians spend hours analyzing photos and other data, which is expensive.