The smell of virgin olive oil may signal the Mediterranean diet to you — and it could also be key, improbable as it may sound, to weight loss. Researchers at the†German Research Center for Food Chemistry have found what seems to be another health benefit of olive oil, already hailed for its antioxidants and for its heart-protecting oleic acid.†Extra virgin olive oil may help a person feel satisfied thanks to its particular aroma.
Olive oil does have a distinctive scent, in part because one of its components is a compound called†hexanal, which some thinks smells like fresh-cut grass.
Dr. Malte Rubach, a nutritional scientist, and her colleagues came upon their finding about olive oil and satiety while doing research on how four different fats — lard, butter, olive oil and canola oil — influence feelings of fullness. 120 participants were randomly divided into five groups and instructed that they were to eat 500 grams of yogurt every day for three months. One group, the control group, had plain, zero-fat yogurt while those in the other four groups ate yogurt enriched with one of the four fats. All participants were given routine blood tests.
At the end of the three months, the group that had eaten the olive oil yogurt had the greatest increases in blood levels of serotonin, a hormone associated with satiety. In addition, those in this group had, for the most part, lowered their caloric intake to take the extra daily yogurt into account and had not, as a result, gained weight. Those in the butter and control groups had also not gained weight. But those in the canola and lard groups had as they had not cut back on the overall calorie consumption along with the extra yogurt.
Canola oil is, like olive oil, recommended as a healthy alternative as a cooking oil; it contains less saturated fat than other oils and also less monosaturated fat than other oils. As†canola oil has properties that are similar to that of olive oil, Dr. Rubach and the other scientists were “particularly surprised” that it produced such different results and concluded that something besides nutrients in canola and olive might be leading to the different results.
They conducted a second trial, dividing participants into two groups and having both eat zero-fat yogurt — but one group’s yogurt contained an aroma extract with the scent of olive oil. The results are intriguing: the participants who ate the plain yogurt not only said they felt less satisfied after eating it, but their serotonin levels fell. They also increased their overall intake of food by an average of 176 calories a day.
In contrast, the participants who ate the yogurt with olive-oil flavoring ate fewer calories from other foods and showed better responses in glucose tolerance tests, which measure blood sugar control — variations in this leads to sensations of hunger and satiety.
Earlier research about how we know we’re satisfied has focused on flavor and taste. It’s not just what you see on your plate (like the amount of a food) or how your taste buds react that can affect your satiety but unseen factors, such as aromas. How foods are packaged and labeled also plays a part: knowing that a food is low-fat can actually lead to people compensating and eating more, as Rubach says to the New York Times.
Could it be that it’s not yogurt in flavors reminiscent of dessert that we ought to help ourselves to, but one that instead has the savor of a nice green salad dressed with olive oil?
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