The shells of pistachios have a special benefit – they may slow down consumption.
According to James Painter, PhD, RD, Chair of the School of Family and Consumer Sciences at Eastern Illinois University in the United States, the “Pistachio Principle” is caloric reduction without calorie restriction. It is one of the many ways we can alter our environmental cues, allowing us to become more mindful and satisfied with our food choices. He completed two studies that found that individuals could reduce their overall calorie consumption without consciously restricting their diets.
Pistachios are satisfying
In his first study, individuals self-selected either in-shell or shelled pistachios. Because the shells act as a natural barrier, taking longer to remove, the in-shell group consumed 41% less than the shelled nut group. And yet they reported feeling equally as satisfied as the group consuming more.
Pistachio Shell Offers Visual Cue
In Dr. Painter’s second study, in-shell pistachios were consumed over an 8-hour shift. On the first day the empty shells were left on the desks as a visual “reminder” of consumption and on the second day the shells were removed. Results showed that when the shells were left on the desk as a visual cue subjects consumed 23% fewer calories.
Interestingly, despite the reduction in calories, they reported feeling equally as satisfied as the control group that consumed more calories.