Postprandial peptide YY is lower in young college-aged women with high dietary cognitive restraint.

Acylated ghrelin and peptide YY (PYY3-36) are involved in appetite-regulation and energy homeostasis. These gastrointestinal hormones provide peripheral signals to the central nervous system to regulate appetite and short term food intake, and interact with leptin and insulin to regulate energy balance. Dietary restraint is an eating behavior phenotype that manifests as a conscious cognitive control of food intake in order to achieve or sustain a desired body weight. The purpose of the current study was to determine if college-aged women (18 to 25 years) with different eating behavior phenotypes, i.e., high vs normal dietary restraint, differ with respect to circulating concentrations of gastrointestinal hormones during and following a test meal. We hypothesized that women with high dietary cognitive restraint [High CR (score ≥ 13, n=13)] would have elevated active ghrelin and PYY3-36 concentrations after a test meal compared to women with normal dietary cognitive restraint [Normal CR (score < 13, n=30)]. Gastrointestinal hormones were assessed before (-15 and 0 min) and after (10, 15, 20, 30, 60, 90, 120 and 180 min) the consumption of a mixed composition meal (5.0 kcal per kg/body weight). In contrast to our hypothesis, mean PYY3-36 concentrations (p=0.042), peak PYY3-36 concentrations (p=0.047), and PYY3-36 area under the curve (p=0.035) were lower in the High CR group compared to the Normal CR group after controlling for body mass index. No group differences were observed with respect to acylated ghrelin before or after the meal. In conclusion, PYY3-36 concentrations were suppressed in the women with High CR compared to the women with Normal CR. While the current study is cross-sectional and cause/effect of high dietary restraint and suppressed PYY3-36 concentrations cannot be determined, we speculate that these women with high cognitive restraint may be prone to weight gain or weight re-gain related to the suppressed circulating PYY after a meal. Further investigations need to explore the relationship between dietary cognitive restraint, circulating PYY, and weight gain.