Sick of weighing your food to measure the right portion size?
Researchers from the University of Sydney's Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders have developed a portable and easy-to-use method to help people estimate portion size -- using only your hands.
This new development will make it easier for those who are watching their weight to calculate the appropriate portion size for discretionary (or junk) foods.
We spoke to Alice Gibson, the accredited practising dietitian and PhD candidate at the University of Sydney who led the study, to understand more about this handy method.
"There are a lot of different ways to estimate portion sizes. The most accurate is to weigh it but if you're out and about you don't have access to that," Gibson told The Huffington Post Australia.
If we can help people to more accurately estimate their portion sizes then that will help people to watch their energy intake for whatever their goals are.
"This idea came about when I was presented with a plate of lasagna and I thought 'how am I going to put this into my food diary?' I realised people would have to classify it as small, medium or large or mentally imagining to squish it into a cup, but that is really hard and can lead to inaccurate measurements."
After researching other methods of measuring food portions -- such as using a ruler, which no one wants to carry around -- Gibson came up with the idea to use the things we always have on us: our hands.
"I thought, there's got to be a better way to measure it. I then came up with the idea of measuring it with your hands.
"Foods conform to certain shapes -- for example, lasagna is a box, a glass of wine is a cylinder and cake or pizza is a wedge or triangular prism. I thought if we measure the dimensions and we know the calculations to calculate volume, then we can estimate the weight of the food more objectively and accurately."
This may sound complicated (and bring back memories of those painful high school maths classes), but once this development is translated into a smartphone app, all you will need are your (clean) fingers and your discretionary food of choice.
"The Dietary Guidelines give us types and amounts of foods we should be eating for optimal health. Foods are categorised as core foods and non-core foods (or 'discretionary choices'), which are high in sugar, fat, salt and alcohol," Gibson told HuffPost Australia.
A great example of a discretionary choice would be a cake.
"The Guidelines are based on an energy equivalent within a food group. A serve of discretionary foods is about 600 kilojoules or 150 calories. But if you were out and about and trying to limit your intake of cake to that amount of energy, you wouldn't know how many calories are in that piece of cake.
"In a lot of smartphone applications it will say 'one slice' but a slice can be a 30 gram tiny slither or a quarter of a cake. This hand method is a tool to help guide you to the appropriate amount of food to eat."
So, how does the finger width method really work?
"The idea is you would use a ruler to do a one-off measurement of the width of four of your fingers," Gibson said. "Then when you go to eat lasagne you enter the number of fingers it is. For example, if it's 7 by 5 by 4 fingers, it would tell you how much energy it is or how many grams the portion size is."
By understanding the true energy of your treat, it helps you to know how much or how little you can enjoy without going outside your discretionary choice amount.
"It helps you limit the foods that are high in energy and are going to have a bigger contribution to your total energy intake, rather than, say, a salad. It's more for foods we should try to limit in our diet as opposed to foods that are good for us," Gibson said.
"For these discretionary foods that are high in energy, if you're off by 50 grams of a piece of cake, that's going to be a much bigger error in terms of energy than if it was 50 grams of vegetables."
Another practical application of the finger method for discretionary foods is alcohol.
"A standard drink of wine is going to look completely different depending on the size of the wine glass," Gibson told HuffPost Australia. "If you have a glass of wine and you want to meet the guidelines and have one standard drink a day, you could measure out 120ml and measure how many fingers high the wine falls to."
Once you know how many fingers 120ml of wine equates to, you can simply use your fingers as a guide for wine from then on -- providing it's in the same glass.
You can also use this method for foods such as pizza because, although we wish otherwise, there's no one set amount of calories for pizza with its various toppings, thickness or size.
"Once you've used the method a couple of times, you will know that a slice of pizza four fingers wide is the right portion because, depending on the pizza, the thickness and size of that slice varies greatly," Gibson said.
"It might be a thin and crusty base or a thick, fluffy base, so knowing the height would help you to find the right portion."
Some foods and drinks do not fit into the five food groups because they are not necessary for a healthy diet and are too high in saturated fat and/or added sugars, added salt or alcohol and low in fibre.
These foods and drinks can also be too high in kilojoules (energy).
Many tend to have low levels of essential nutrients so are often referred to as 'energy-dense' but 'nutrient-poor' foods.
The problem is that they can take the place of other more nutritious foods.
Also, the higher levels of kilojoules, saturated fat, added sugars, added salt and/or alcohol that they contain are associated with increased risk of obesity and chronic disease such as heart disease, stroke, type 2 diabetes and some forms of cancer.
While the finger width method is not a definitive, 100 percent accurate form of measuring food and it doesn't yet take into account the food's ingredients or personal goals, the method was found to be more accurate than household measures (cups and teaspoons) and size descriptions for estimating food portions.
The next step now is to fine tune the method and bring it to app developers. Basically, watch this space.
"I'd love to talk to app developers. If we can help people to more accurately estimate their portion sizes, then that will help people to watch their energy intake for whatever their goals are," Gibson said.