But whether these products are effective or not is a matter of dispute: While it is true that they contain fewer calories, people tend to overcompensate by eating more if they do not feel full. Now a study has shown how “natural” oils and fats regulate the sensation of feeling full after eating, with olive oil leading the way. So what makes this oil so effective?
Work groups at Technische Universität München (TUM) under Prof. Peter Schieberle and at the University of Vienna under Prof. Veronika Somoza studied four different edible fats and oils: Lard, butterfat, rapeseed oil and olive oil. Over a period of three months, the study participants ate 500 grams of low-fat yoghurt enriched with one of the four fats or oils every day – as a supplement to their normal diet.
The results were conclusive: The olive oil group’s calorie intake remained the same, but the control group had been consuming an extra 176 kilocalories per day. Schieberle explains: “The aroma group adapted their eating habits – but the control group participants were obviously not able to do likewise. We also found that in comparison to the other group, the control group had less of the satiety hormone serotonin in their blood.”
Direct impact on blood sugar level
How long the feeling of satiety lasts after eating depends on a number of factors, but blood sugar level is particularly significant. The faster it falls, that is to say, the faster the somatic cells absorb glucose from the blood, the sooner the person will start to feel hungry again. In the next part of their study, the researchers investigated which of the aroma substances present in the oil are most effective at inhibiting glucose absorption.
The researchers used olive oils from Spain, Greece, Italy and Australia for their study. The research team managed to identify two substances that reduce the absorption of glucose from the blood in liver cells: Hexanal and E2-Hexenal. They also discovered that Italian olive oil contained larger amounts of the two aroma compounds.
“Our findings show that aroma is capable of regulating satiety,” concludes Schieberle. “We hope that this work will pave the way for the development of more effective reduced-fat food products that are nonetheless satiating.”
P. Schieberle, V. Somoza, M. Rubach, L. Scholl, M. Balzer; Identifying substances that regulate satiety in oils and fats and improving low-fat foodstuffs by adding lipid compounds with a high satiety effect; Key findings of the DFG/AiF cluster project “Perception of fat content and regulating satiety: an approach to developing low-fat foodstuffs”, 2009-2012.