New microwave can count calories on your plate

A new 'smart' microwave may not only heat your food but also tell you how healthy it is by calculating the number of calories in your meal.
The device works by passing low-energy microwaves through a weighed portion of food and measuring how the microwaves are changed by the food - fat and water affect the microwaves in characteristic ways.
The device so far works on blended foods - the prototype requires a homogeneous mixture to get an accurate reading.
Researchers are developing a version of the device that will determine the calories in a plate of food and send the information to your smartphone.

Matt Webster, senior scientist in diagnostic imaging and biomedical technologies at General Electric (GE) Research who invented the calorie counter, said the device might be eventually incorporated into a microwave oven or some other kitchen appliance.
Webster said that it is possible to get an accurate calorie estimate using just three pieces of data - fat content, water content, and weight.

According to MIT Technology Review, the calories from all the other constituents of food - such as sugar, fibre, and protein - can be approximated by subtracting the water and fat weight from the total weight.
In tests using the device to measure mixtures of oil, sugar, and water, results were within 5 to 10 per cent of the results from standard, destructive means of measuring calorie content, the report said.

Getting a reading is easy using existing equipment if the food is liquid or blended. A good reading for a sandwich and chips will require "virtual blending", Webster said.