Researchers found 26 study participants who ate a diet high in polyunsaturated fats (PUFAs) for a week had higher levels of peptide YY, which is associated with satiety, and lower levels of ghrelin, a hormone related to hunger. After a seven-day period, they ate a diet high in saturated fats again. Both diets contained the same number of calories and proportion of calories from fat, and differed only in the type of fat.
Combined with participants’ feedback, researchers concluded higher PUFA levels were more likely to leave consumers feeling full.
One of the three macronutrients alongside protein and carbohydrates, fat is essential for a healthy body. But an oversimplified public health message in the 1980s led many consumers to believe that instead of replacing saturated fat with polyunsaturated fat, it should be avoided as much as possible. This caused an explosion of low-fat foods on the U.S. market, which often were made more palatable with added sugars.
However, the "healthy fat" message is finally beginning to get through, according to Mintel. The research firm says that global mentions of "good fat" on new products are on the rise thanks to improved consumer awareness. According to the Dietary Guidelines for Americans, there is strong and consistent evidence that replacing saturated fat with polyunsaturated fat is linked to fewer heart attacks and less incidence of cardiovascular disease. Even with this increased awareness, U.S. consumers still eat too much saturated fat — with an average of 19% of total calories coming from solid fats — despite dietary advice that it should be responsible for less than 10%.
Satiety has been a major focus for food manufacturers, but the recent attention has been on protein. Earlier research also has pointed to polyunsaturated fat for its effects on satiety, and though many scientists previously thought fat in general had a lower effect on satiety than other macronutrients, there is a growing body of research to suggest that fats — and polyunsaturated fats in particular — could be just as satiating as protein or carbohydrates.
The researchers behind this latest study suggest that increasing consumption of foods like walnuts, canola oil and salmon could actually prevent over-consumption of meals high in saturated fats. If further studies back this claim, it would give the "good fats" message another boost.