7/7/2011 --- A new study now appearing in the peer-reviewed British Journal of Nutrition, finds that fat in pistachios may not be completely absorbed by the body. The randomized controlled-feeding study, which is the first-of-its-kind research with nuts, indicates that pistachios may actually contain fewer calories per serving than originally thought. Conducted by the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA), the study shows pistachios to be one of the lowest calorie nuts with 160 calories per 30 gram serving (approximately 1 ounce).

The research measured the energy value of pistachios by feeding 16 healthy adults the nuts as part of a controlled diet and calculating the energy value from differences in energy excretion during the dietary treatment timeframe. The resulting energy value of one 30-gram serving of pistachios was 5.9 percent less than previous calculations.

"Pistachios convey a variety of health benefits, including weight management support and cardiovascular support," said lead ARS researcher David J. Baer, Ph.D., supervisory research physiologist with the Beltsville Human Nutrition Research Center. "This study underscores the valuable role pistachios can play in a balanced diet in contrast to the common misperception to exclude nuts from the diet to reduce caloric intake."

Additional data from the newly published study reinforces the heart-health benefits of pistachios. The ARS researchers found that when healthy individuals included 1.5 and 3 ounces of pistachios into their typical American diet, cardio-supportive results were shown.

In addition to the new data on pistachios, a recent study by researchers at Harvard University – Boston, suggests diet and lifestyle influence long-term weight gain. The consumption of nuts, as well as vegetables, whole grains, fruits and yogurt, was inversely associated with weight gain with nuts exhibiting a (-).57 pound effect on body weight. Poor diet and lifestyle choices compound over time, ultimately leading to long-term weight gain; however, the practice of mindful eating can reinforce weight management support.

The new data demonstrating the potential calorie savings of pistachios builds on previous research showing that pistachios are a weight-wise snack. According to researchers at the University of California – Los Angeles, choosing to snack on pistachios rather than pretzels not only supports body mass index (BMI) goals, but can support heart health, too.

In a 12-week randomized study, 52 overweight and obese subjects were placed on a 500-calorie deficit diet and assigned to either a pistachio snack (about 75 pistachios providing 240 calories) or a pretzel snack group (two-ounces of pretzels providing 220 calories). The results showed that the pistachio group had better success with supporting their BMI goals compared to the pretzel group, showing pistachios can be included in a healthy diet, even for those managing their weight.

Additionally, pistachios – also known as the "Skinny Nut" – are shown to be a "mindful snack" in terms of taking longer to eat and requiring the snacker to slow down and be more conscious of what has been consumed. According to behavioral eating expert, James Painter, Ph.D., R.D., Chair of the School of Family and Consumer Sciences at Eastern Illinois University, "Our research shows in-shell snackers eat 41-percent fewer calories than those who snack on shelled nuts. We also found that in-shell pistachios offer a visual cue to help reduce intake. When leftover shells are cleared immediately, snackers eat up to 22 percent more compared to leaving left over shells as a reminder of consumption. "

Pistachios are also a good source of fiber and protein. Providing about 49 kernels per 30-grams (approximately 1 ounce) serving, pistachios offer the most nuts per serving when compared to other popular snack nuts – comparatively, almonds have 23 in a serving, walnuts 14 halves and cashews, 18.

References
Mozaffarian D, Hao T, Rimm EB, Willett WC, and Hu FB. Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men. The New England Journal of Medicine.2011;364(25), 2392-404.
Li Z, Song R, Nguyen C, Zerlin A, Karp H, Naowamondhol K, Thames G, Gao K, Li L, Tseng CH, Henning SM, Heber D. J Am Coll Nutr. 2010; 29(3):198-203.
Honselman CS, Painter JE, Kennedy-Hagan KJ, Halvorson A, Rhodes K, Brooks L, Skwir K. Consuming Unshelled Pistachios Reduces Caloric Intake. Journal of the American Dietetic Association. 2010;110(9), A57S.
Kennedy-Hagan KJ, Painter JE, Honselman CS, Halvorson A, Rhodes K, Skwir K. Pistachio Shells Serve as a Visual Cue of Calorie Consumption. Journal of the American Dietetic Association. 2010;110(9):A58S.