Motivation and emotion/Book/2013/Eating and emotion

Overview
At times the desire to eat goes beyond a basic physiological or survival response. Food can be inextricably linked to our emotions, whether its the giant slab of chocolate cake we reach for after a particularly harrowing exam, or the way food is as unpalatable as a bowl of ashes after a break-up. Sometimes it feels good to eat good food. Why are we so much happier after finishing a plate of salmon and steamed vegetables? Is it a conscious response because we know we have done something that will benefit us, or are there deeper biological factors coming into play?


 * Emotion : "A positive or negative experience that is associated with a particular pattern of physiological activity." - Wikipedia page: Emotion

Emotion regulation - structures
Several gut hormones or peptides - leptin, ghrelin, glucagon-like peptide 1 (GLP1) and insulin, in particular - have been found to influence emotions and cognitive processes (Gómez-Pinilla, 2008). Leptin, for example, is a hormone that is synthesised in adipose tisssue, and its receptors have been identified in several brain areas, including the hypothalamus, the cerebral cortex, and the hippocampus. Gómez-Pinilla (2008) reported that genetically obese rats with dysfunctional leptin receptors had higher instances of long-term depression, and impairments in both long-term potentiation and spacial learning. These conditions were effectively reversed by administering leptin into the hippocampus (Gómez-Pinilla, 2008).

The motivation-and-reward system which is activated by eating is the same one which regulates the positive-valence emotion provoked by drinking, sexual behaviour, and drugs of abuse (Méndez-Díaz, Rueda-Orozco, Ruiz-Contreras & Prospéro-Garciá, 2010). While dopamine appears to be the leading factor behind this reward system, endorphins and endocannabinoids also have a role (Méndez-Díaz, Rueda-Orozco, Ruiz-Contreras & Prospéro-Garciá, 2010). Méndez-Díaz, Rueda-Orozco, Ruiz-Contreras and Prospéro-Garciá (2010) explained that several natural and artificial cannabinoids - tetrahydrocannabinol (THC), WIN-55212 and CP-55940, for example - enhance both the dopaminergic neurons, and dopamine release in forebrain rewarding areas. They continued by saying that cannabinoids are involved in the regulation of food intake; THC, for example, increases regular food intake, and CP-55940 increases sweet food intake through CB1 activation.

Emotion regulation - deficits
Emotional eating theory originated from psychodynamic thinking, and postulates that most people will experience changes in their eating patterns as a direct response to emotional stress. In reality, on average, 30% of people report an increase in appetite or actual food intake, and 48% report a decrease. There is clear evidence that emotions that differ in their valence and arousal or intensity will exert different influences on eating; several studies support the view that high-arousal or intense emotions (e.g., anger) will decrease food intake, but low-to-moderate emotions (e.g., boredom) will increase food intake (as cited in Macht, 2008). In addition, negative emotions such as anger, fear, and sadness may increase impulsive eating, but they also decrease food pleasantness. Conversely, joy and other positive emotions are shown to increase both food pleasantness and the consumption of foods that are good for us.

Difficulties regulating emotions appear to be involved in both the development and maintenance stages of disordered eating behaviours. One way in which emotional regulation is developed is through emotion socialisation processes, in particular, parental responses to emotion. - Buckholdt, Parra and Jobe-Shields (2009)

The role of parents and upbringing
Buckholdt, Parra and Jobe-Shields (2009) found that parental responses to emotions are related to the development of emotional competence, including the ability to amend one's emotion and behaviour in order to achieve goals. Importantly, if parents invalidated the emotions of their children through minimisation, discouragement or even punishment, it could lead to disordered eating behaviours. Interestingly, it was paternal (but not maternal) emotion invalidation that led to excessive exercising and self-induced vomiting. Individuals whose parents modelled excessive emotion, rather than productive coping strategies, may have had difficulties developing adequate emotion regulation mechanisms. As such, they displayed higher levels of binge eating, and lower perceived control over eating behaviours. It is also worth noting that children may become hesitant to express their emotions if they expect their parents to become distressed, and may be turning to binge eating behaviours as an outlet for their emotions.

Emotional overeating and binge eating disorder
According to Masheb and Grilo (2006), binge eating disorder is characterised by recurrent episodes of binge eating, during which there is a subjective sense of lack of control. It is generally triggered by dysphoric moods (Masheb & Grilo, 2006). They found that overeating as a response to anxiety was the most common trigger, followed by sadness, loneliness, tiredness, and anger. They noted that women were more likely than men to overeat as a response to loneliness.

One of the factors that has been found to increase episodes of binge eating in binge eating disorders (including bulimia nervosa) are negative emotions (Macht, 2008). Accordingly, Gianni, White and Masheb (2013) hypothesised that individuals with eating disorders are vulnerable to engaging in emotional overeating because they lack adaptive emotion regulation strategies and skills, including those associated with being able to clearly identify and adaptively cope with emotional states. Obese individuals with Binge Eating Disorder (BED) often experience negative mood affect, and they either lack the strategies necessary to overcome these emotions without eating, or the otherwise functional strategies they do possess are inadequate for the level of emotional discontent they are experiencing.

Manzoni, Pagnini, Gorini, Preziosa, Castelnuovo, Molinari and Riva (2009) ran an experiment, in which obese women receiving treatment for emotional eating disorders were provided with three weeks of relaxation training, to complement the usual inpatient treatment they would receive. One group had this relaxation training enhanced by soothing music from a portable MP3 player, another group was enhanced with a virtual reality program, and a control group received no relaxation training (Manzoni, Pagnini, Gorini, Preziosa, Castelnuovo, Molinari & Riva, 2009). They found that the two experimental groups showed a statistically significant difference to the control group for rates of emotional eating, though no differences were detected between the two experimental groups. They postulated that this was due to the relaxation techniques distracting the patients from food images, thereby reducing food cravings. It was surprising, then, that the researchers found no statistical significance between the overall weight between the three groups at the three-month follow up, though they suspected that the result could have been down to both the low response rate (only 40% of the participants across the entire study responded to the follow up), and the short period between the conclusion of the experiment and the subsequent follow up.

Anorexia nervosa
Anorexia nervosa is a severe psychiatric illness, and it was characterised by Manuel and Wade (2013) by the following:


 * attainment and maintenance of low body weight
 * fear of weight gain
 * long term and relapsing course
 * the seeming indifference (of the sufferer) to the gravity of the illness

It is associated with the highest admission rate, and longest median length stays, of all psychiatric disorders; among all forms of mental illness is has the highest health care utilisation, as well as the highest mortality rate (Manuel & Wade, 2013).

Manuel and Wade (2013) reported that women who were in treatment for anorexia nervosa had more difficulties with emotion regulation than healthy control women; however, their problems with emotion regulation decreased as recovery progressed. Brokomeyer, Holtforth, Bents, Kämmerer, Herzog and Friederich (2012) also found evidence that emotion regulation was an issue for anorexia nervosa sufferers, with a study which utilised an autobiographic memory test. Anorexia nervosa sufferers generally displayed increased fear when confronted with emotional stimuli, and recalled more general memories (as opposed to emotive ones) than the healthy control group. In fact, qualitative studies found that patients with anorexia nervosa consistently stated that the disorder helps them to suppress and avoid negative emotions (Brokomeyer, Holtforth, Bents, Kämmerer, Herzog & Friederich, 2012). Most of the previous work that Brokomeyer, Holtforth, Bents, Kämmerer, Herzog and Friederich (2012) found confirmed this; food restriction in anorexia nervosa was undertaken in an attempt to avoid negative affective states, mostly through an obsessive focus on weight, body shape, and food consumption. They concluded that an exclusive focus on feeding and weight restoration deprives the patient of an important coping mechanism, without replacing it with another (more functional) one. Therefore, they continued, skills to regulate aversive emotions had to be taught early in treatment; two which may fit the bill are emotion acceptance behaviour therapy and cognitive remediation and emotion skills training (CREST) (Brokomeyer, Holtforth, Bents, Kämmerer, Herzog & Friederich, 2012)

Disgust
Disgust is a form of emotional food rejection, motivated by both the origin of the offending stimulus, and the contamination capabilities of the offending stimulus. The most basic definition for disgust is "bad taste", and its gustatory basis is due, in no small part, to the evolutionary advantage of not eating food which tastes or smells bad because of spoilage or poison (Olatunji & Sawchuk, 2005). Disgust is one of the key motivating factors behind moral vegetarianism, with moral vegetarians showing higher levels of disgust towards meat-based foods than those who were vegetarian for health reasons.

Please note that this page focuses on emotion, so for a more in-depth look at the motivations behind moral vegetarianism, go to this page (Wikipedia) or this page (Wikiversity).