Daily Consumption of Pistachios over 12 Weeks Improves Dietary Profile Without Increasing Body Weight in Healthy Women: A Randomized Controlled Intervention

Dietary guidelines around the world recommend the regular intake of nuts because of their nutrient contribution to the diet and reported health benefits. However, consumers are often reluctant to include nuts in their diet due to the high caloric density of nuts. In a 12-week randomized, controlled intervention, we investigated how adding a pistachio portion to the daily diet affects body weight and composition, satiety, energy and nutrient intake. Sixty healthy pre-menopausal women who did not typically consume nuts were randomly assigned to a control or an experimental groups. Experimental participants (n = 30) consumed 44 g (250 kcal) pistachios mid-morning while controls (n = 30) maintained their current eating habits for 12 weeks. Ad libitum food intake and appetite sensations following the pistachio portion were assessed in all participants before and after the intervention in four 2-consecutive-day test sessions (under laboratory and then free-living conditions). Body weight and composition (DXA) were unchanged in both groups after 12 weeks. Pre- and post-intervention tests showed that ad libitum intake adjusted to the pistachio portion, mostly via reduced intakes of carbohydrates and starch, in parallel with decreased hunger and increased satiety following the morning snack. Intakes of MUFA, PUFA, linoleic acid, thiamin, pyridoxine, copper, manganese, and zinc were significantly higher among women consuming the pistachio snack, in spite of compensatory adjustments in intake. In conclusion, daily intake of 44 g pistachios improved nutrient intake without affecting body weight or composition in healthy women. The additional calories provided by the pistachios induced satiety and sufficient adjustment of intake to prevent body weight changes. CLINICAL TRIAL REGISTRY NUMBER: NCT03526120https://clinicaltrials.gov/ct2/show/NCT03526120.