At recent meetings of the Illinois Dietetic Association Spring Assembly and the Cornell University Food and Brand Lab Consumer Camp, Dr. James Painter, chair of the School of Family and Consumer Sciences at Eastern Illinois University, and Pistachio Health scientific advisory board member presented some interesting new behavioral research that is currently underway.  Believe it or not, it involves pistachios!

Dr. Painter and his colleagues are investigating how in-shell pistachios can be a more mindful snack, and how they help “trick” the brain into feeling fuller on fewer calories, compared to eating already-shelled nuts.  It’s a way of helping consumers alter their environmental cues so that they are satisfied on fewer calories.

Three plausible hypotheses are being tested:

• Pistachio shells increase the size of a serving—not the calories--giving the perception that a larger serving is being eaten, and therefore, satiety is enhanced;

• The discarded shells act as a visual cue, reminding snackers of how much they’ve eaten; and; 

• Eating an in-shell pistachio requires a conscious decision to open--like opening a food package--and they take longer to eat, S-L-O-W-I-N-G down the rate of consumption. 

In preliminary studies, Dr. Painter found that eating in-shell pistachios helped individuals consume fewer calories without consciously restricting their calories.  Compared to shelled nuts, those who sampled in-shell pistachios ate 50 percent fewer calories and reported feeling equally satisfied.  In a second follow-up study, Dr. Painter found that when empty shells were left on the table, individuals ate 35 percent fewer calories than when the shells were immediately discarded. 

Dr. Painter also presented his Pistachio Principle research last month at Consumer Camp, an annual conference hosted by Cornell’s Food and Brand Lab Team where the latest mindless eating research is presented to health professionals, consumers and fellow Cornell students and alum.  Brian Wansink, author of more than 100 academic articles and books, including the best-selling Mindless Eating: Why We Eat More Than We Think, is the director of the Cornell Food and Brand Lab, and hosts the conference each year.  At this year’s conference, Dr. Painter conducted an impromptu study with attendees.  Small bags of shelled and in-shell pistachios were handed out to the audience with the instructions to “snack on pistachios” during his one-hour mindless eating presentation.  At the end of the presentation, the bags were collected from attendees, and the results tabulated.  The results revealed that on average, those snacking on in-shell pistachios consumed only five nuts while the shelled nut snackers munched an average of 18 pistachios –nearly four times as many!

While the studies are ongoing, I’m betting on the fact that in-shell pistachios may help us cut calories without feeling deprived.

Kelly Plowe, MS, RD

Although she still remains a Boston sports fan, Kelly has changed her east-coast ways, adapting to the California lifestyle.