Background and aim: Globally, Western food availability and variety have increased substantially in the recent decades. Concurrently, obesity levels are continuously rising inducing increased risk of diabetes, cardiovascular disease, cancers, and other diseases. A lower demand for physical activity in combination with changes in food accessibility and eating behaviors are suggested as main cause of obesity. This calls for further understanding of how the food surrounding us affects our behavior, mental state, and physiology. This involves a complex
interplay of both internal and external signals including motivation, emotions, hormones, and central neural integration. Moreover, as humans we are consciously aware of some of these processes relating to appetite control, whereas others are outside of our awareness. The rationale for this PhD thesis was to contribute novel methodologies to examine both explicit and implicit aspects of appetite control behaviors and to add to the
current knowledge of the multifactorial determinants affecting food choices and food intake. The overall aim was to study food reward and to explore how biometric responses related to food reward and food intake in different populations. More specifically, we wanted to examine food reward and biometric responses to food cues, i.e. images of foods varying in fat content and sweet/savory taste and to explore the relationships with food intake.
Methods: Two cross-sectional studies and one interventional study formed the basis of the content of this thesis. We examined food reward using the Leeds Food Preference Questionnaire (LFPQ) as well as the Steno Biometric Food Preference Task (SBFPT); the latter was developed as part of the PhD project. The SBFPT combined measures from the LFPQ with biometric measures from eye tracking, electrodermal activity (EDA),
and facial expressions. The SBFPT was first tested in 100 adults with normal weight in a cross-sectional study, the PRESET study, (Paper I and II) and secondly, it was implemented in a large ongoing randomized controlled trial, the REStricted Eating Time (RESET) study (Paper IV). The PRESET study examined food intake from an ad libitum buffet meal. The RESET study was set forward to examine the effects of 12 weeks of time-restricted eating, an intermittent fasting regimen, in 100 adults with overweight and obesity at high risk of developing type 2 diabetes. As this study is still ongoing, only the protocol paper is included in this thesis. In the second cross-sectional study, food reward was assessed in an Inuit population in Greenland using the LFPQ as part of a study examining the effects of four weeks on a traditional Inuit diet (TID) vs. a Westernized diet (WD) (Paper III).
Results and conclusion: We developed a novel methodological approach to concurrently examine measures of food reward and different biometric responses. In the PRESET study, maintained attentional responses from eye tracking revealed positive associations with measures of food reward and food intake. Biometric responses from EDA and facial expressions were not associated with food reward or food intake, except for negative
facial expressions, which were associated with lower liking for foods (Paper I). Moreover, from examining differences between food categories that varied in fat content and sweet/savory taste, we found that responses differed for maintained attentional responses as well as for measures of food reward and food
intake (Paper I). When applying a machine learning approach to studying data from the PRESET study, separate or combined measures of biometrics or food reward were not strong predictors of food intake (Paper II). Lastly, this thesis presents the first data on food reward in an Inuit population: After four weeks of following either a TID or a WD, participants only differed in implicit wanting for high-fat sweet foods that was higher for the TID group (Paper III). In both groups, participants had overall lower preferences for sweet over savory and lower preferences for high-fat over low-fat foods. Together, the papers highlight relationships between biometric measures, food reward, and food intake and provide insight into both explicit and implicit food-related behaviors in different populations. This thesis emphasizes the complexity of appetite control and the many diverse aspects affecting food intake.
|Translated title of the contribution||Undersøgelser af madbelønning og biometriske målinger i relation til kostindtag|
- University of Southern Denmark
- Jørgensen, Marit Eika, Principal supervisor
- Quist, Jonas Salling, Co-supervisor, External person
- Finlayson, Graham, Co-supervisor, External person
- Petersen, Tue Hvass, Supervisor, External person
- Heide, Kiara, Co-supervisor, External person
|Date of defence||20. Apr 2022|
|Publication status||Published - 29. Mar 2022|