PRESET study - Evaluation of methods for measuring gastrointestinal transit and food reward in healthy individuals

Appetite and food intake are intricately regulated and affected by both physiological and behavioural factors. The gastrointestinal (GI) tract plays an important role in the physiological regulation of appetite through mechanical, endocrine and neuronal processes. GI transit can be measured using a wireless capsule technique (SmartPillTM) ingested in combination with a granola bar (SmartBarTM) which has a composition that differs significantly from a standard western meal. Dietary intake is not only controlled by metabolic factors but also behavioural factors including food reward, pleasure and palatability on eating.

These components can exist with and without conscious awareness, and preferences and choices; however, there is a need for methods to assess these aspects of food intake. Furthermore, few studies have investigated the interplay between the physiological and implicit and explicit aspects of appetite regulation and food intake.


The aims of the PRESET study are to:

  1. Evaluate the effects of a solid mixed meal vs. a SmartBarTM on GI transit times measured by the SmartPillTM technology in healthy normal-weight individuals.
  2. The examine whether biometric signatures (eye tracking, facial expression, galvanic skin response) from exposure to pictures of food during a computer task (Leeds Food Preference Questionnaire (LFPQ)) correlate with explicit and implicit measures of food reward, intake, and choices during a subsequent ad libitum buffet meal.
  3. Examine potential associations between measures of food reward and eating behaviour traits, GI transit time, metabolic markers of appetite, and subjective appetite

Design: The study consists of two sub-studies:

  • An observational cross-sectional study including 100 healthy normal weight adults. Food preferences and explicit and implicit aspects of food reward and preferences will be assessed using LFPQ and biometric measurements.
  • A randomized cross-over study including 15 participants from study 1. On two separate test days participants will ingest the SmartPillTM together with a SmartBarTM and a standard mixed breakfast meal, respectively. Metabolites, hormones, food preferences and explicit and implicit aspects of food reward will be assessed in the fasting and postprandial state

Primary outcome: Difference in gastric emptying time after the SmartBarTM and the mixed meal.
Secondary outcomes include but are not limited to:

  • Small bowel transit time, large bowel transit time and total transit time measured using the SmartPill™ technique
  • Metabolites and hormones involved in regulation of appetite and metabolism
  • Subjective appetite
  • Attention measured by eye tracking during the LFPQ
  • Emotions measured by facial expression during the LFPQ
  • Arousal measured by galvanic skin response during the LFPQ
  • Measures of food reward and food choice examined during the LFPQ
  • Energy intake and food choice during the ad libitum buffet meal
  • Body composition measured using Dual-energy X-ray Absorptiometry
  • Glycemic variability measured by continuous glucose monitoring
  • Resting energy expenditure and substrate oxidation
  • Heart rate variability
  • Blood pressure and heart rate


University of Copenhagen
Aalborg University Hospital
University of Leeds, UK
iMotions A/S