Mock up of a calorie counting device

GE Research has developed a prototype of a microwave that could someday measure calories in the foods that a user warms up, according to a report from MIT Technology Review. This first prototype is only capable of measuring the caloric content of some liquids.

GE Global Research Senior Scientist Matt Webster invented the device when he was looking for a way to make a passive nutrition tracker for his wife, who told him activity trackers were not useful without this feature, according to a blog post in GE Reports.

After combing through U.S. Department of Agriculture nutritional information on 6,500 foods, Webster found that he could get a mostly accurate calorie count from the food's fat content, water content, and weight. He told GE Reports that a microwave can detect fat and water signatures because "water and fat interact with microwaves very differently".

“I wanted to boil it down to a simple recipe that determined calories from a small handful of data points,” Webster said. “Perhaps I could measure those data points with sensors and use them to calculate the calories in any food.”

So far Webster's experiments can only measure calories in a mixture of syrup, oil and water. These experiments took place Baylor University’s Department of Electrical and Computer Engineering. Now the team is working on building a microwave that can also identify calorie counts in a plate of food and then send the data to the user's smartphone.

While consumers don't use a microwave for all of their food, it looks like GE is one step closer to passive nutrition tracking, a feature several companies have been working towards recently.

In June, new research came out that suggests a device worn on the wrist could some day track hydration, pulse, and even blood glucose non-invasively. Two papers published in Biomedical Optics Express, the journal of the Optical Society, explained that researchers used a technique called the speckle effect to learn about chemical reactions happening under a user's skin. Researchers using this technique shine a low-intensity laser on the skin and observe the pattern of reflection. If researchers want to specifically test for glucose consumption, they use a magnet to alter the polarization state of the light and make the speckle patterns more detectable.

Two other companies, Airo and Healbe, landed in hot water after announcing their passive nutrition tracking wearable devices. Airo, which started taking preorders for its device in October 2013, informed its early backers a month later that it would refund their money after reports came out that the device may not deliver on its promises. The company added that it would not put the device back up for sale until it was tested and validated further.

Though Healbe had a successful round of preorders on crowdfunding site Indiegogo, raising $1,081,445, well over its $100,000 goal, critics also questions its device's capabilities and according to a recent report from Pando Daily the company no longer claims its device can passively track calories.