Two studies published in the current on-line issue of the journal Appetite indicate that consuming in-shell pistachios is a weight-wise approach to healthy snacking, offering unique mindful eating benefits to help curb calorie consumption.
The first study found that participants who consumed in-shell pistachios ate 41% fewer calories compared to those who ate shelled pistachios.
The second study revealed that pistachio nut shells can provide important "visual cues" as a reminder of consumption that translate into reduced calorie consumption. Both studies further underscore that in-shell pistachios, which are one of the lowest calorie nuts, are a practical, everyday snack for weight management.
The first study involved 140 university students assigned to consume either in-shell pistachios or shelled pistachios during class time. Both groups of students were provided a 16-ounce cup and asked to self-select a portion of pistachios to consume during class.
Each student's cup of pistachios was weighed before consumption began. As students left the classroom, the remaining pistachios were weighed and recorded; total weight and calories from the consumed pistachios was also calculated. Those who chose shelled pistachios consumed an average of 211 calories while those who chose in-shell pistachios consumed an average of 125 calories, a 41% decrease in calorie intake.
The second study examined the potential role of pistachio shells as visual cues of intake. Study subjects included 118 faculty and staff from a Midwestern university, all of whom were provided a pre-weighed 16-ounce bowl filled with four ounces of in-shell pistachios to keep on their desk over the course of two workdays.
Participants were told they could consume pistachios at their leisure during the day and were also provided a second 16-ounce bowl to discard the pistachio empty shells.
The subjects were assigned to one of two groups. For the first group, the bowls with pistachio shells were not emptied until the end of the day. For the second group, the bowls with pistachio shells were emptied every two hours. Pistachios were added in two-ounce portions if the amount in the bowl had been reduced to half or less of the starting amount.
When leftover pistachio shells remained on the desk throughout the day, calorie consumption of pistachios decreased by 22% compared to when nut shells were routinely removed.
This is in keeping with existing research showing that when a person has visual cues of 'leftovers,' such as pistachio shells, they can see how many or how much they have eaten, helping to control portion size and consumption.
Pistachios are one of the lowest calorie nuts with 160 calories per 30 gram serving (approximately 1 ounce or 49 kernels).
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