Examining the Role of Perceived Body Boundaries and Spatial Frame of Reference in the Effect of a Mindfulness Meditation in Emotional Eating

Emotional eating, or overeating in response to negative emotions is problematic because the overconsumption of high-caloric and high-fat foods can result in weight gain and obesity. It has also been linked to binge eating in bulimia nervosa and binge eating disorder.

Thus far, research examining the processes underlying emotional eating has used a number of different methods including self-report questionnaires, laboratory studies, and testing in naturalistic settings. Recently, our team used qualitative methodology to understand the phenomenology, or first-person subjective experience, of individuals while emotionally eating. The investigators interviewed eight individuals who emotionally ate and collected 16 hours of interview data using explicitaiton interviews, a type of interviewing method developed by Pierre Vermersch that aims to access an individual's phenomenology of an event by guiding them to relive the event in the present moment through a body-centered perspective. Preliminary thematic analysis of the data showed that most of the individuals described a theme of "thinking a lot" in response to negative emotions that they experienced. This is in line with a narrative focus that involves linking subjective experiences through time using thoughts of self-traits, traits of others, memories of the past, and aspirations of the future. In response to this narrative mode of functioning, individuals then described themes of "looking forward to the sensory experience" of food and consequently "enjoying the sensory experience," "not thinking about my stressors," and "being in the moment" while eating. This shift to sensory experience is in line with an experiential focus that involves inhibition of cognitive elaboration in favor of attending to present-moment sensory objects, including feelings and sensations rooted in the body.

The two modes of self-focus seen in our qualitative study of the phenomenology of emotional eating map on to modes of psychological functioning at the level of the self as described by, which can be used to understand how self-related processes impact emotional eating in order to help individuals reduce this behavior. Specifically, the theme of "thinking a lot" or rumination seen in our qualitative study can be mapped onto what Gallagher describes as the narrative self, characterized by mental activities such as thoughts, emotions, and motivations, linked to one's past and future. In this state of functioning, mental contents are experienced in a way that is identified with one's self, called experiential fusion or cognitive fusion, which leads to the perception of being the one who is thinking the thoughts or experiencing the emotions. While such a perception is adaptive for cognitive and social functioning (such as through a central locus of control, sense of identity, etc), an overemphasis on the sense of self, particularly when it is negative, is maladaptive. For example, narrative self-functioning that is high in rumination, negative self-judgments, cognitive fusion, and mind-wandering has been linked to a variety of psychopathologies, such as anxiety and depression. On the other hand, themes of "being in the moment", "enjoying the sensory experience," etc. seen in our qualitative study can be mapped onto what Gallagher describes as the minimal self, also referred to as the embodied self, because it consists of basic or core processes that are phenomenologically related to the body, such as sensorimotor experiences, sense of agency, and sense of ownership. In addition, the minimal self, dependent on sensory processing, is thought to allow for the parsing of "self" from "not-self" through body-based processes, such as shifts in perceived body boundaries and spatial frames of reference. Specifically, perceived body boundaries describe the degree to which the self is experienced as a discrete, body-encapsulated entity, separate and isolated from the surrounding world. Thus, when one perceives their body boundaries as more salient, a greater sense of separation of oneself from others and the environment is experienced. When one's body boundaries are perceived as more diffuse, higher levels of happiness are experienced. Similarly, the spatial frame of reference describes the region within one's perception, often based in the body and construed as the self, that is involved in the sense of connection between self, others, and the environment. Particularly, one's spatial frame of reference may be experienced as egocentric, or through a self-centered preoccupation with internal, private events, constraining the sense of self within the physical body's boundary, or allocentric, through distributed feelings of unity and interdependence with the others and the environment. More diffuse body boundaries and more allocentric frames of reference have been found to be associated with greater compassion for self and others, altruism, and psychological wellbeing.

One way to engage with the minimal self and increase wellbeing outcomes without relying on eating is through the practice of mindfulness, described as "paying attention in a particular way: on purpose, in the present moment, and non-judgmentally." For example, during the body scan meditation, a type of mindfulness practice, individuals are instructed to intentionally shift their attention to various parts of the body and to notice what happens without judging or reacting. If thoughts and emotions arise, they are briefly noted, and attention is shifted back to the body. This attention training facilitated a shift of attention from a thought-based narrative focus to sensory-based interoceptive awareness through cognitive defusion, or the ability to gain psychological distance from thoughts and feelings by seeing them as mere events in the mind, and equanimity, or an even-minded mental disposition towards all objects of experience regardless of their affective valence or source. As such, by practicing a body scan meditation, individuals are able to reduce focus on self-specifying cognitive processes that differentiate the self from not-self and experience more diffuse perceived body boundaries and more allocentric frame of reference, which lead to increased positive emotions and decreased negative emotions. Recent research has investigated the influence of the mindfulness meditation on emotions, perceived body boundaries, and spatial frames of reference. For example, Dambrun studied the effect of a body scan mindfulness meditation on happiness and anxiety and found a greater reduction in the salience of perceived body boundaries in the body scan condition compared to the control condition. Furthermore, he found that the change in perceived body boundaries was accompanied by an increase in happiness and decrease in anxiety and that the change in happiness was mediated by the change in perceived body boundaries. Similarly, a study by Hanley and Garland showed that a brief mindfulness practice encouraged more allocentric frames of reference and that more allocentric frames mediated the effect of mindfulness induction on affective state by increasing positive affect and decreasing negative affect. Finally, Hanley found that five sessions of mindfulness meditation training decreased perceived body boundaries and encouraged more allocentric frames of reference and that the effect of mindfulness training on allocentric frames of reference was mediated by decreased perceived body boundaries.

Within emotional eating, negative emotions lead to overeating through food cravings and an inability to down-regulate them. A food craving is defined as an intensely strong desire for a specific food or type of food. Recently, research has shown that mindfulness practices are effective in reducing negative emotions and the intensity of food cravings. Particularly, the body scan meditation has been shown to reduce rumination, improve emotion regulation, decrease negative affect and increase positive affect. However, no research so far has examined the effects of the body scan meditation on the intensity of food cravings through the reduction of the negative emotions that elicit the craving. Given the empirically supported ability of the body scan meditation to facilitate changes in the perceived body boundaries and spatial frames of reference and to consequently reduce negative emotions, the investigators can expect that reduced body boundaries and a more allocentric frame of reference will mediate the ability of the body scan meditation to reduce negative affect and cravings. Finding such effects through the hypothesized mechanisms would contribute to the knowledge on how mindfulness-based exercises exert their positive influence. Furthermore, if the body scan is found to be an effective means of reducing negative affect and consequently the intensity of food cravings, it could be recommended to emotional eaters as one practice to regulate their emotions and eating behaviors.

Thus, the current study will use a pre-post randomized-controlled study to examine whether the body scan reduces induced negative affect and food cravings in emotional eaters through reduced salience of body boundaries and a more allocentric spatial frame of reference. The investigators predict that emotional eaters in the body scan condition will report more diffuse body boundaries, a more allocentric frame of reference, and lower rumination than emotional eaters in the control condition and that this will mediate reduced negative affect and, thereby, reduced cravings. Furthermore, the investigators predict that mindfulness, equanimity, cognitive defusion, and interoceptive awareness will act as moderators of the influence of the body scan meditation on negative affect and food cravings because individuals who score high on these variables will be more likely to benefit from the body scan meditation.