Breaking a bar of chocolate up into squares may help you lose weight, scientists have found.
The findings can also apply to other foods, experts believe, with cutting up and spreading out food a tactic anyone can employ for any foods to help them eat less.
Controlling portion size is a key aspect of dieting and weight control, alongside exercise and a balanced diet.
A team of researchers at Shaanxi Normal University in China looked at whether turning food into more, smaller chunks affected how people perceive portion size, and also if spreading it out made a difference.
A total of 63 people took part in two experiments where they looked at 60 different pictures of chocolate arranged in various ways.
“The results demonstrated that unit number and inter-unit distance independently influenced the perception of overall portion size,” the scientists write in their study, published in the journal Food Quality and Preference.
Food spaced out appears like more
The team showed the participants a block of chocolate, with 10 different sizes, and it was then either cut into nine or 16 pieces and either not spread out, or there was 10, 20 and 30 per cent extra space between the squares.
Study author Fei Wu told The Telegraph that due to how portion sizes are viewed in our head the distance and larger number of smaller chunks tricks us into thinking there is a larger portion than there actually is.
“Of course, the key to helping people lose weight is to increase the perceived portion size of the food,” he said.
“Although real food was not used in the experiments, based on the experimental results, we can speculate that people who want to lose weight can arrange their food on a plate in a slightly scattered way and leave some space between each item. This will make the food look like more.
“Conversely, if the same amount of food is gathered together, it will look like less, which may make you feel like you can eat more.
“In addition, the food can be divided into more units, such as cutting a loaf of bread into multiple pieces, which makes the overall portion size of bread look like more.”
Perceived portion size can mediate consumption
Wu initially got the idea for the study when noting the different stacking techniques employed by friends while at a buffet.
“The buffet operated on a weigh-and-pay system, where food was selected, weighed, and charged accordingly,” Wu said.
“As my research topic was related to portion size, I suggested that we estimate each other’s food portion size.
“During this process, I noticed that one friend’s plate had loosely arranged food with gaps in between, forming a large circle that caused everyone to overestimate the price of the food.
“In contrast, another friend’s plate had tightly stacked food forming a small circle, resulting in the food being undervalued. This prompted me to explore how the presentation of food affects perceived portion size.”
Previous studies have shown that perceived portion size is worth studying because it can mediate consumption. If a person can perceive food as being bigger than it is, for example, then they may judge food as too large and reduce their consumption.
“When perceiving overall portion size, both unit number and inter-unit distance influenced overall portion size estimation,” Wu said.
“When the same portion size of food was cut into 9 or 16 pieces, individuals perceived the 16-piece was larger than the nine-piece.
“Additionally, when the food pieces are separated (e.g an inter-unit distance of 120 per cent or 130 per cent), consumers can perceive more overall portion size than clustered (e.g an inter-unit distance of 100 per cent).
“To increase the perceived portion size, you can increase the unit number. This way, when estimating the overall portion size from the unit portion size estimate value, a larger overall portion size estimate value can be obtained.
“In real life, this situation might correspond to estimating a whole box of cookies by one cookie.”