We all know that eating the right portion sizes can help us maintain a healthy weight, but knowing exactly what counts as a sensible portion can be difficult.
In the video above, Alice Gibson, a practising dietician and PHD student at the university, says you can estimate the volume of food using the formula: Volume = 1/2 x width x length x height.
She then demonstrates how you can use your hands to roughly calculate each of the measurements for a slice of lasagne.
In the example of the lasagne, you do 1/2 x width (7) x length (5) x height (4) to estimate the volume in grams.
”There’s no really good way to actually estimate how much you’re eating unless you’re going to whip some scales out of your bags, so we wanted to find a more objective way for people to quantify what they’re eating when they’re out and about,” Gibson said.
In a trial of the method, 67 participants were asked to estimate the portion sizes of 42 pre-weighed foods and liquids.
The researchers found that 80% of food sizes assessed using the hand method were within 25% of their true weight.
Gibson said more research is needed to fine-tune the process, but she hopes it will be incorporated into an app where you’ll enter your finger widths as well as your height and your weight to find out the right portion sizes for you.