A pecan-enriched diet reduced postprandial appetite intensity and enhanced peptide YY secretion: A randomized control trial.

Background & Aims: Tree nuts have been shown to have satiating qualities; however, little is known concerning the effect of pecans on measures of appetite. The purpose of this study was to examine the impact of a pecan-enriched diet on subjective, physiological, and direct measures of appetite in older adults.

Methods: This was a randomized, controlled trial in which healthy older adults (50-75 y) were randomized to either consume 68 g of pecans/day (pecan; n = 21) or avoid all nuts (control; n = 23) for 4 weeks. At pre- (V1) and post-diet (V2) visits body weight (BW) and body fat percentage (BF) were assessed and actual change in these outcomes for pecan were compared to theoretical changes if pecans were consumed without compensation. Subjective appetite was measured using visual analog scale (VAS), and blood was collected to assess changes in physiological appetite before and every 30 min for 4 h following a high-fat meal. Energy intake (EI) at a buffet meal was then assessed in the laboratory ("in-lab"). VAS assessments continued hourly for the next 7 h and EI ("at-home") was self-reported.

Results: BW and BF did not change for pecan or control across the intervention and theoretical change in BW (theoretical: 2.2 ± 0.1 vs. actual: 0.4 ± 0.2 kg; p < 0.0001) and BF (theoretical: 0.4 ± 0.04 vs. actual: 0.2 ± 0.2%; p < 0.0001) was significantly greater than actual change for pecan. From V1 to V2, there was an increase in fasting (pecan: 77.0 ± 4.6 to 93.5 ± 6.1 vs control: 76.0 ± 5.0 to 72.5 ± 5.0 pg/mL; p = 0.01) and postprandial peptide YY for pecan vs. control (p = 0.04); however, fasting and postprandial cholecystokinin and ghrelin did not differ (p > 0.05). There were no differences in the change in subjective appetite ratings at fasting, following the high-fat meal (in-lab), at-home, or across the full day between groups (p > 0.05 for all). However, there was a significant suppression of peak desire to eat ratings for pecan vs. control (pecan: 67.9 ± 4.6 to 57.1 ± 5.2 vs. control: 61.9 ± 4.2 to 60.6 ± 4.3 mm; p = 0.04). Combined, buffet meal, and at-home EI did not differ significantly within pecan and control; however, there was a trend (p = 0.11) for a between group difference in buffet meal EI driven by increased EI for control (+137 ± 86 kcal) vs. decreased EI for pecan (-45 ± 77 kcal).

Conclusion: A 4-week pecan-enriched diet led to enhanced satietogenic metrics compared to a diet void of all nuts. As weight remained stable during the intervention, adding pecans to the daily diet may be beneficial to appetite control and weight maintenance in a healthy older population.

Trial Registration Information: ClinicalTrials.gov: NCT04385537.