Diet and Personality

Keller & Siegrist (2015) took a random sample of 951 people from the general population and examined direct and indirect influences of the big five personality traits on eating styles and food choices. While high openness to experience and high agreeableness were both associated with low meat consumption, path models revealed that high openness to experience also equated to lower soft drink intake and high vegetable, fruit and salad consumption. Greater fruit and less meat consumption was also linked to conscientiousness (through promotion of restrained eating and reduction of external eating). In addition to this restrained eating and reduced external eating, those with high conscientiousness were prevented from consuming sweet and savory foods due to emotional eating. On the other hand, neuroticism promoted emotional and external eating and thereby encouraged eating sweet and savory food. Keller & Siegrist (2015) list many associations between personality traits with eating styles and food choices including extraversion with sweet and savory, meat and soft drink intake via advocating external eating. Furthermore, results suggest that neurotic and emotionally unstable individuals seem to adopt counter-regulatory external or emotional eating and eat high-energy dense sweet and savory foods. Whereas, highly conscientious individuals adopt regulatory dietary restraint and practice counter-regulatory emotional or external eating less, resulting in higher consumption of recommended and less intake of foods not recommended. The study found that the higher sociability of extroverted people seems to have negative effects on health. It was concluded that the more proximal, counter-regulatory eating styles such as emotional or external eating might be more successfully addressed in interventions to prevent overeating and overweight.

Sariyska et al. (2019) carried out two studies to find correlations between personality traits, particularly involving emotional systems, with dietary habits such as eating a vegan/vegetarian/omnivore diet for example. In the first study, the link between the Dark Triad personality traits (narcissism, Machiavellianism, and psychopathy) and dietary habits was explored, in addition to the relationship between individual differences in primary emotional systems and dietary patterns. Study 1 was tested on 1140 individuals, while study 2 had 444 participants. The second study also aimed to replicate the associations between the Dark Triad traits and dietary habits in a new sample. The Affective Neuroscience Personality Scales (ANPS) were applied to assess individual differences in six primary emotional systems, while the Short Dark Triad Scale (SD3) was administered to assess individual diversity in Machiavellianism, psychopathy and narcissism, and the Eating Behavior Questionnaire (EBQ) was employed to measure eating style. The results of Study 1 showed higher CARE, SADNESS and spirituality scores, and lower PLAY scores in vegans/vegetarians than in omnivores, although this trend involving CARE weakened after accounting for sex of the participants. In omnivores, high Machiavellianism scores were observed, but this relationship disappeared once sex was considered. Machiavellianism scores were elevated in the second study for the omnivores relative to the vegans/vegetarians, as well as their scores for narcissism and psychopathy. However, these trends weakened or disappeared after the sex of the subjects was added to the model again. Hopefully these two studies might help to better understand how people following different types of diet, might differ in their personalities.

Since the personality traits neuroticism, extraversion, openness, agreeableness, and conscientiousness are linked with resilience (adaptability to challenging situations) and resilient people usually comply with favorable health behaviors, Tiainen et al. (2013) decided to study the associations between food and nutrient intake, personality traits and resilience. A validated semi-quantitative food frequency questionnaire was used to measure diet and the NEO-personality inventory to assess personality in 1681 subjects. After adjusting for various factors such as age and education, openness in men was found to be linked with higher vegetable consumption and lower intakes of chocolate and confectionery. In women, the openness trait also correlated to more vegetables in the diet, as well as fruits. Including more vegetables in the diet was also associated with extraversion in women although higher meat consumption was also linked. Moreover, agreeableness was associated with a lower soft drink and conscientiousness with a higher fruit intake in women. Interestingly, when resilient and non-resilient subjects were compared, resilience in women was found to be associated with higher consumption of vegetables, fruits, fish and fiber. These results suggest personality traits are associated with dietary intake - especially subjects with resilient personality profiles had healthier dietary intakes. The associations were also stronger in women than in men.

Pänkäläinen et al. (2018) regards personal traits as a possible explanation for why some people manage to adapt to a healthier diet while others are not so successful in changing their dietary habits. Since dispositional optimism has been suggested to have a role in effecting positive dietary patterns, this study aimed to determine the roles of both optimism and pessimism in the process of dietary changes. Dispositional optimism and pessimism were measured using the revised Life Orientation Test in 2815 individuals (aged 52-76 years) participating in the GOAL study in Lahti, Finland. The subjects’ dietary habits were also analysed at baseline and after 3 years to gauge the progress. The results indicated pessimism was negatively associated with healthiness of eating habits at baseline while optimism was correlated to a lesser extent to eating patterns at baseline. In addition, those who showed improvements in eating behavior and those who considered their diet as healthy enough without intervention were found to be the subjects less pessimistic at baseline, when compared to individuals who failed to alter their diet in a positive way or those who did not attempt to change. The research concluded that pessimism reduces independently the possibility to improve dietary patterns, and that pessimistic people are more likely to eat a less healthy diet than others.

Since it has been proposed that personality may be linked to dietary choices, this 2014 review evaluated the evidence for an association between the Big Five dimensions of personality with dietary consumption, and compliance to dietary recommendations. Lunn et al. (2014) inspected findings from cross-sectional surveys conducted in various countries and cultures and noted a positive association between openness and consumption of fruits and vegetables, as well as a correlation between conscientiousness and healthy eating. Although no evidence was found that associated personality dimensions with adherence to dietary recommendations over time, conscientiousness was discovered to be connected to prosocial and health-promoting behaviors such as avoiding alcohol-related harm, binge-drinking, smoking, and adherence to medication regimens. Poor dieting is a known risk factor for becoming overweight/obese, and associated chronic lifestyle diseases. After revealing that higher conscientiousness was associated with behaviors beneficial to health, this review hypotheses that this personality trait may predict adoption of healthy dietary and other lifestyle recommendations.

Mõttus et al. (2012) experimented on 1,691 Estonian adults, all aged between 18 and 89, to examine the relationship between personality traits and dietary habits. Eleven items were used to measure dietary habits of the sample population which identified two dietary patterns: health-aware, defined by increased consumption of cereal, dairy products, fish, fruits and vegetables; and traditional, which included diets high in potatoes, bread, and meat-containing products. Also, the Five-Factor Model personality traits (Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness) along with 6 facets of each trait, were measured using the NEO Personality Inventory-3. Diets that scored highly in the health aware factor were connected to lower neuroticism, and higher extraversion, openness and conscientiousness; while higher scores on the traditional diet factor were linked to lower levels of openness. The possible barriers to diet change identified by these findings could potentially assist in designing future dietary interventions.

The purpose of this 2020 cross-sectional study was to assess whether optimism is associated with overall diet quality, food group consumption and snacking. Ait-Hadad et al. (2020) retrieved data of 32,806 adult participants from the NutriNet-Santé study, including their dispositional optimism [obtained by using the Life-Orientation Test Revised (LOT-R)], overall diet quality (assessed by the mPNNS-Guideline Score), snacking behavior (evaluated by an ad hoc question), and consumption of 22 food groups (utilising at least 3 self-reported 24-h dietary records). The results revealed connections between optimism with greater overall diet quality, less snacking (OR = 0.89), and higher intakes of fruits and vegetables, seafood, whole grain, fats, dairy and meat substitutes, legumes, non-salted oleaginous fruits. However, negative associations also existed between optimism and consumption of meat and poultry, dairy products, milk-based desserts, sugar and confectionery. Although no association was found between optimism and energy intake, higher consumption of alcoholic beverages and appetisers were linked to the optimism trait. These findings suggest that optimism could be considered for the promotion of a healthy eating behavior.

Bénard and colleagues (2019) set out on a mission to assess whether impulsivity was associated with energy intake, food-group consumption, and risk of eating disorders (EDs). the 51,368 participants of the NutriNet-Santé Study were used since impulsivity, food-group consumption and diet quality, snacking behavior, and risk of EDs were all documented in this 2014 study through the Barratt Impulsiveness Scale (BIS-11), ≥3 self-reported 24-h dietary records, an ad hoc question, and the Sick-Control-One-Fat-Food Questionnaire (SCOFF), respectively. This allowed the identification of categories of ED such as bulimic, hyperphagic, and restrictive. The results showed impulsivity was positively associated with consumption of alcoholic beverages and appetisers, and negatively linked to intakes of food groups such as fruits and vegetables, meat and poultry, processed meat, dairy products, milk-based desserts, and starchy foods. Higher impulsivity also appeared to positively relate to snacking (OR = 3.32) and with energy consumption. Moreover, poorer diet quality and greater ED risk was connected to the personality trait. The strongest associations were found for bulimic disorders (with an odds ratio of 4.38) and hyperphagic disorders (OR = 2.91). This study declared that impulsivity could be taken into account in future promotions of healthy eating behavior.

Previous studies have connected the temperament trait with risk factors for chronic disease, but this 2018 study by Perälä and her team aim to examine the cross-sectional associations between temperament and diet. Firstly, information on the 1668 adults (aged 56-70, male and female) who took part in the Helsinki Birth Cohort Study were taken. Dietary consumption was determined by a validated 128-item food frequency questionnaire, while temperament was measured using the Tridimensional Personality Questionnaire. The temperament trait was broken down by the following: novelty seeking (NS); harm avoidance (HA); reward dependence (RD); and persistence (P). Greater HA related to poorer diet quality (less vegetables, fruits, fish and a number of vitamins in the diet), whereas RD was linked to higher consumption of vegetables and vitamin E, and lower alcohol intake. The temperament trait NS was significantly connected to diets consisting of more fish, fat, alcohol, and less cereals, carbohydrates and milk products. P was not associated with any of the food groups or nutrients in this study. Perälä et al. (2018) was able to discover associations between temperament traits and diet, particularly noting the correlations between greater harm avoidance with poorer diet quality, and higher reward dependence with healthier diets.

Since personality influences lifestyle behaviors - particularly dietary behavior - Jurado et al. (2012) thought it was possible to associate personality with adherence to the Mediterranean diet pattern (MDP). This study analysed this possible relationship by recruiting 2016 patients (all aged 18-65) at a primary health service in Granada, Spain during 2007 to 2008. In addition to the questionnaire on socio-demographics, personality, and MDP the participants underwent personality tests using the Temperament and Character Inventory (TCI-125) and were examined on adherence to the MDP using the validated 14-point Mediterranean Diet Adherence Screener (MEDAS). After controlling for multiple variables, the MEDAS score was found to be directly associated with individual self-directedness, age, and minor psychiatric morbidity score. The inverse relationship was seen between MEDAS score with BMI and marital status (widowed, separated or divorced). These findings suggest highly self-directed people may respond better than others to diet advice, and taking into account these various personalities may prove helpful in designing interventions hoping to enhance MDP adherence. Jurado et al. (2012) proposed offering more intensive professional support and counseling for those patients with low self-directedness.

The purpose of this 2018 study was to develop a reliable and valid instrument that could measure the extent to which people are confident in their ability to adhere to the Mediterranean diet. This instrument was named the Self-Efficacy Scale for Adherence to the Mediterranean Diet (SESAMeD). The study was carried out in two stages, with stage 1 set to assist with reducing and refining the list by administering the pilot questionnaires to 170 students. Stage 2 involved evaluating the reliability and validity of the scale by testing on 348 patients who had previously suffered from a cardiovascular disease. Following the evaluation, the items of the scale could be reduced to 22. The factor structure of SESAMeD was tested across exploratory factorial analysis and confirmatory factorial analysis, with both analyses confirming a robust adjustment for the bi-factorial structure. The two factors identified were: self-efficacy for the avoidance of determined unhealthy foods not recommended in the Mediterranean diet; and self-efficacy for the consumption of determined healthy foods recommended in this diet. The pattern of relations between the SESAMeD and the SESAMeD subscales and other different psychological variables (outcome expectancies, motivation, affective balance, and life satisfaction) supported the validity of the bi-factorial structure and provided strong evidence of construct validity. Cuadrado et al. (2018) have designed an instrument that can help healthcare professionals and researchers to assess patients’ confidence in managing to adhere to the Mediterranean diet, a psychological variable that may in fact affect adherence itself to this healthy eating habit.

Although there is evidence that people’s overall level of meat consumption is related to the Big Five personality traits (extraversion, agreeableness, openness, conscientiousness, and neuroticism) and sociodemographic factors, Pfeiler & Egloff (2018) believe there are important differences among the various types of meat that may play a factor in how the intakes of specific meat types are associated with personality and sociodemographics. The two researchers conducted 2 studies to clarify whether these general and specific relationships are true, using two large-scale samples from Germany (13,062) and Australia (15,036). In the results, sociodemographic and personality variables showed specific associations with meat intake, depending on type of meat. In both studies, openness was negatively related to red meat consumption but positively associated with fish intake but in hierarchical regression analyses controlled for sociodemographic factors, openness was not related to poultry nor overall meat consumption. By contrast, extraverted people reported both more consumption of each individual type of meat and more overall meat consumption. The author does realise that although the results were largely consistent between the samples, effect sizes were generally small. Nevertheless, Pfeiler & Egloff (2018) exposes the importance of differentiating between the types of meat when examining individual variations in meat consumption and making associations using these outcome measures. The implications of these findings and future avenues for exploring the link between personality and dietary habits are discussed further.

The purpose of this 2018 study was to discover differences in personality, if any, between vegetarians and omnivores. Forestell & Nezlek (2018) recruited 276 vegetarians (those who avoided meat and fish), 1191 semi-vegetarians (those who ate meat and/or fish), and 4955 omnivores. After measuring the participants’ personality (the five factor model) and depressive symptoms, it was apparent that vegetarians and semi-vegetarians were more open to new experiences, while also showing signs of being more neurotic and depressed than omnivores. No variations in conscientiousness nor agreeableness as a function of eating habits could be found. These differences in personalities between vegetarians and semi-vegetarians with omnivores identified might help improve our comprehension of individual differences in food preferences.

According, against, and above dietary norms: a key to understanding the relationship between personality style and taste preferences

Examining the "Veggie" personality: Results from a representative German sample

Diet-induced impulsivity: Effects of a high-fat and a high-sugar diet on impulsive choice in rats (animal)

Individual differences in impulsivity and need for cognition as potential risk or resilience factors of diabetes self-management and glycemic control