A necklace that keeps track of what people eat by distinguishing crunching sounds is the first wearable gadget to monitor calorie intake.
Paired with a smartphone via Bluetooth, the high-tech necklace is equipped with a sensitive microphone the size of a zipper pull that records the sounds emitted when the subject is eating. The information is subsequently sent to a smartphone, where it is analysed and compared against a library of chewing sounds.
"There is no shortage of wearable devices that tell us how many calories we burn, but creating a device that reliably measures caloric intake isn't so easy," explained Wenyao Xu, computer scientist at University at Buffalo, who is developing the device together with researchers from Northeastern University in China.
The technology is based on the fact that different types of food result in distinct sounds when chewed. In a recent experiment, the necklace was able to determine with 85 per cent accuracy whether one of the 12 test subjects involved in the study was eating apples, carrots, potato chips, cookies, peanuts or walnuts, or alternatively drinking water.
The researchers envision the device could one day help people keep track of how much calories they consume but also help them spot which foods may be causing them digestive problems. That would be particularly beneficial for people with metabolic disorders and chronic bowel problems.
Xu admits that the technology has certain limitations as it has no means for distinguishing individual ingredients in complex meals, such as soups or curries.
In future, it could thus be paired with a biomonitoring device that would activate automatically when the necklace determines that the user is eating a complex meal.
The biomonitor would use a set of measurements to determine blood sugar levels and other indicators to provide advice on healthy eating.
The researchers call the device AutoDietary. It wraps around the back of the neck like a choker necklace. The researchers said it would only be active when the user is eating. However, they did not specify how they would ensure that. The minute microphone could certainly present a certain privacy risk.