Foods produced with olive oil or olive oil aromas in place of other oils or fats could help consumers feel fuller for longer, according to new research.
The findings come after scientists from Germany and Austria compared the effects of four different edible oils on feelings of satiety.
Led by Professor Peter Schieberle from the Technische Universität München (TUM), Germany, and Professor Veronika Somoza from the University of Vienna, Austria, the team gave study participants a low fat yoghurt that had been enriched with either lard, butterfat, rapeseed oil or olive oil.
"Olive oil had the biggest satiety effect," said Schieberle. "The olive oil group showed a higher concentration of the satiety hormone serotonin in their blood."
"Subjectively speaking, these participants also reported that they found the olive oil yoghurt very filling," he said.
Schieberle commented that the findings "surprised us", because both rapeseed oil and olive oil contain similar fatty acids.
In a further extension of the study, the team found that it is in fact the aroma compounds found in olive oil that help to increase satiety, and not the oil itself.
Schieberle and his colleagues gave consumers the yoghurt containing one of the four fats as a supplement to their normal diet for a period of three months. In this time, participants consumed 500 grams of the enriched yoghurt every day.
During the study period, no member of this group recorded an increase in their body fat percentage or their weight.
However it was found that those consuming the olive oil product had increased levels of satiety hormones and lower reported feelings of hunger.
A matter of smell?
To try and explain these findings, the team turned their attention to the aroma compounds found in olive oil - by performing a follow up study where one group was given yoghurt with olive oil aroma extracts and a control group was given plain yoghurt.
The results were conclusive: The aroma extract group's caloric intake remained the same, while the control group consumed an extra 176 kilocalories per day.
"The aroma group adapted their eating habits – but the control group participants were obviously not able to do likewise," said Schieberle.
"We also found that in comparison to the other group, the control group had less of the satiety hormone serotonin in their blood."
"Our findings show that aroma is capable of regulating satiety," he concluded.
"We hope that this work will pave the way for the development of more effective reduced-fat food products that are nonetheless satiating."