title: The time-varying association between perceived stress and hunger within and between days.
abstract: OBJECTIVE
  Examine the association between perceived stress and hunger continuously over a week in free-living individuals.
  
  
  METHODS
  Forty five young adults (70% women, 30% overweight/obese) ages 18 to 24 years (Mean = 20.7, SD = 1.5), with BMI between 17.4 and 36.3 kg/m(2) (Mean = 23.6, SD = 4.0) provided between 513 and 577 concurrent ratings of perceived stress and hunger for 7 days via hourly, text messaging assessments and real-time eating records. Time-varying effect modeling was used to explore whether the within-day fluctuations in stress are related to perceived hunger assessed on a momentary basis.
  
  
  RESULTS
  A generally positive stress-hunger relationship was confirmed, but we found that the strength of the relationship was not linear. Rather, the magnitude of the association between perceived stress and hunger changed throughout the day such that only during specific time intervals were stress and hunger significantly related. Specifically, the strength of the positive association peaked during late afternoon hours on weekdays (β = 0.31, p < .05) and it peaked during evening hours on weekend days (β = 0.56, p < .05).
  
  
  CONCLUSIONS
  This is the first empirical study to demonstrate potentially maladaptive, nonlinear stress-hunger associations that peak in the afternoon or evening hours. While we are unable to infer causality from these analyses, our findings provide empirical evidence for a potentially high-risk time of day for stress-induced eating. Replication of these findings in larger, more diverse samples will aid with the design and implementation of real-time intervention studies aimed at reducing stress-eating.
authors: Institute for Prevention Research, University of Southern California, Los Angeles, CA, USA.
authors: Jimi
authors: J
authors: Huh
authors: Bouve College of Health Sciences, Northeastern University, Boston, MA, USA.
authors: Mariya
authors: M
authors: Shiyko
authors: Department of Psychology, Hawaii Pacific University, Honolulu, HI, USA.
authors: Stefan
authors: S
authors: Keller
authors: Institute for Prevention Research, University of Southern California, Los Angeles, CA, USA.
authors: Genevieve
authors: G
authors: Dunton
authors: Department of Behavioral Science, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. Electronic address: sschembre@mdanderson.org.
authors: Susan M
authors: SM
authors: Schembre
mesh_terms: D000328:Adult; D001066:Appetite; D015992:Body Mass Index; D059026:Diagnostic Self Evaluation; D004435:Eating / Q000523:psychology*; D002149:Energy Intake; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D006801:Humans; D006815:Hunger; D008297:Male; D009765:Obesity / Q000523:psychology; D010465:Perception; D010507:Periodicity; D012527:Satiation; D012528:Satiety Response; D013315:Stress, Psychological / Q000150:complications; D055815:Young Adult
keywords: Ecological momentary assessments; Hunger; Stress eating; Text-messaging; Time-varying effect modeling