Science Spotlight: Is Your Personality Causing You to Gain Weight?

Personality, Chrononutrition, and Cardiometabolic Health: A Narrative Review of the Evidence

Personality traits summarize patterns in how people typically think, act, feel, and behave. The basic personality traits which are developed early on in life appear to remain relatively stable over time. At the very least, personality traits are not easy to change, unless elaborate therapeutic interventions are undertaken. As a result of these consistencies, considerable interest in how personality may affect dietary patterns and weight-relevant behavior has emerged. 

Several different models are available for describing the construct of personality. One of the most popular being The Five-Factor Model (FFM). The FFM is composed of five general dimensions (extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience) each possessing its own unique adjectives and sub facets. 

Extraversion is described as assertive, energetic, and outgoing, with sub facets of excitement-seeking and gregariousness. Agreeableness is described as sympathetic, kind, and trusting, with sub facets of straightforwardness, altruism, and tender-mindedness. Conscientiousness is described as organized, planful, and thorough, with sub facets of self-discipline, achievement-striving, and dutifulness. Neuroticism is described as anxious, tense, and worrying with sub facets of anxiety, hostility, self-consciousness, and impulsiveness. Lastly, openness is described as imaginative and curious, with sub facets of fantasy, aesthetics, and values. 

Numerous studies have been conducted that demonstrate a link between personality traits and obesity, as well as for certain dietary patterns. This recent review compiles the most up to date research on the topic. Let’s take a look at the results.

Personality and Eating Patterns

Personality traits were shown to be strongly correlated with eating styles and personal food choices, with the primary findings revolving around the traits of conscientiousness and neuroticism.

Conscientiousness was positively associated with higher cognitive dietary restraint and greater regulation of emotional and external (eating in response to food cues, i.e. advertisements) eating. It was also shown to be associated with consuming more fruits and vegetables, avoiding salty foods, and regular breakfast consumption and meal times. Unsurprisingly, conscientious individuals were also less likely to snack.

Neuroticism was found to be linked with a higher occurrence of emotional and external eating as well as the consumption of sweet and savory foods. Neuroticism was also suggested to be associated with disordered eating.

While findings were mixed and unsubstantial for the other traits, the authors noted some evidence that shows an association between extraversion and openness with consuming a healthier diet.   

Personality and Obesity

The results displayed that conscientiousness was consistently associated with a lower body mass index (BMI) and decreased risk of obesity. In contrast, it was found that those scoring high in neuroticism tended to have a higher BMI and experienced more frequent weight fluctuations (yoyo dieting). 

The association between the other remaining personality traits and obesity were inconsistent. Some research has found agreeableness and extraversion to be associated with a higher BMI, while other research has not. Conflicting evidence has been reported for openness as well.

Further Evidence

The results of this study are in line with the findings of a previous review on the topic which found conscientiousness to be a protective factor against the development of becoming overweight. Furthermore, it has been shown that individuals who score low in conscientiousness possess a higher cardiometabolic risk as evidenced by insulin resistance, dyslipidemia, central adiposity, and elevated blood pressure.

When considering the characteristics of conscientiousness, it’s not surprising to learn that this general trait is associated with a decreased risk of obesity. Individuals that score high in conscientiousness demonstrate high levels of self-discipline and self-control. As such, they are more likely to follow a healthy diet and engage in health-promoting behaviors in general. The high self-control resources of these individuals might help to maintain their diet goals by resisting tempting food situations.

Those who are conscientious make a deliberate effort to control food intake and display low levels of emotional and external eating. In modern societies with an overabundance of cheap, energy-dense, hyper-palatable food, it can be assumed that the majority of people have a genetic disposition that makes the development of a normal body weight impossible. This is especially true if their eating behavior is not cognitively controlled and intake of food is not consciously restricted in a goal-oriented fashion.

Another factor that has been hypothesized to explain why conscientious individuals are able to maintain a healthier weight is meal consistency. As reported above, individuals that score high in conscientiousness tend to eat meals at the same time each day and at regular intervals. For more information on the metabolic benefits of this practice, be sure to check out my article on snacking.

Similar to the findings of the current review, the totality of the evidence tends to support an association between neuroticism and overweight and obesity. These results are most consistent when it comes to the sub facet of impulsiveness.

Individuals with traits related to impulsivity (and low self-discipline) may find it more difficult to commit to healthy diets, restrained eating, and regular physical activity, which are typically necessary to maintain a healthy weight. This sub facet is suggestive of an inability to control cravings and urges which explains the reported association with poor food choices.

Neuroticism tends to be associated with less restrained eating but enhanced emotional and external eating and is linked to disordered eating behavior (i.e. binge eating).  Overall, it seems that neurotic individuals are likely to participate in counter-regulatory emotional eating. This manifests as the consumption of energy-dense foods (typically sweet and savory items), presumably to cope with negative emotions. 

While results are less consistent for the personality traits of extraversion, agreeableness, and openness to experience (and thus play less of a role in predicting risk for obesity), it’s worth briefly diving into some of the most interesting and relevant findings on these traits.

Openness to experience has been associated with daily servings of fruits and vegetables among college students and with a higher fiber intake in older adults. To explain these findings, it has been suggested that individuals who score high in openness may have started early to repeatedly try fruits and vegetables. As a result, their food preferences changed and they learned to replace sweet, salty, and fatty foods with their healthier counterparts. Taken together, these findings suggest scoring high in openness could correlate with a decreased risk of obesity.

For extraversion, it has been hypothesized that despite inconsistent results across studies, this trait would go hand in hand with overweight and obesity. Individuals that score high in extraversion are more social. These individuals might eat with other people more often and therefore expose themselves more often to hyper-palatable and energy-dense food items, resulting in an increase in external eating.  

In addition, sensation or “excitement seeking” is a particularly relevant feature associated with extraversion. Individuals with an especially strong presence of this quality are sensitive to positive environmental stimuli and are more likely to engage in reward-seeking behaviors when they experience positive emotions. 

This sub facet has been linked to increased calorie consumption, preference for sweets and fast food, impulsive decision making, and loss of control. As such, similar to neuroticism, individuals who score high in extraversion may be more susceptible to our current obesogenic environment. Overall, it’s likely that extraversion is better correlated with an increased risk of obesity.

Practical Takeaway

The above evidence demonstrates that personality traits tend to correspond with distinct eating patterns and weight-related behaviors. In combination with the idea that personality traits remain fairly stable throughout the lifespan, it seems that assessing an individual’s personality may be a worthwhile screening tool to determine obesity risk. 

To further cement the potential application of this screening tool and to provide some more practical insight, we can look at other related evidence. The most relevant being the practices of those who are successful at losing weight and keeping it off.

A recent review analyzed the behavioral characteristics of participants included in several weight control registries around the world. The researchers found that the most successful strategies for losing weight seemed to be the best for keeping it off.

As a quick side note, weight control registries are more or less a cohort of people who have successfully lost a significant amount of weight and have kept the majority of it off for an extended period of time. 

The most frequently reported strategies included increasing vegetable consumption, increasing intake of protein-rich foods, increasing intake of fiber-rich foods, regular breakfast consumption, regular meal frequency, conscious food selection, limiting the intake of certain foods (especially ones high in fat), decreasing alcohol and sugar-sweetened beverage consumption, and self-monitoring via self-weighing and counting calories.

Another study looked at the behaviors of successful individuals from the Weight Watchers program. On average, these subjects lost 24.7 kg through the intervention and maintained 9.1 kg of that weight loss for 3.3 years. 

The results displayed that compared to weight-stable obese controls, individuals who lost a significant amount of weight and kept a large portion of it off, reported significantly greater practice of strategies to support healthy dietary choices, self-monitoring, and psychological coping. 

Specifically, these individuals consumed more servings of fruits and vegetables, kept a bodyweight graph, recorded calories/points, and kept a daily calorie/point goal. They also reported greater willingness to ignore food cravings and if they regained weight, or got off track with their diet, they thought about past successes and used self-encouragement to think positively.

When analyzing this data in conjunction with what we learned about personality traits, it becomes even clearer why conscientiousness tends to be protective against obesity and neuroticism seems to be associated with a greater BMI.

The behaviors of successful weight losers and maintainers require a great deal of self-discipline and control. It takes the utmost diligence to track your body weight and food intake, and follow a structured meal pattern on a regular basis. In addition, it requires a very strong-willed and even-keeled person to not only say no to the plethora of tasty and fattening treats in our modern food environment but replace those with less palatable high-fiber and protein options. Ultimately, highly conscientious individuals feel they have a duty when it comes to their body composition goals and through their achievement-striving nature, they take pride in consistently checking the boxes that facilitate progress in their pursuit.  

On the other side of the coin, neurotic individuals may be less able to consistently adhere to the previously reported habits for weight loss/maintenance success through a susceptibility to experience negative emotions and a lack of control over these emotions. These factors may predispose individuals who score high in this trait to easily fall off the wagon, resulting in a lack of consistency following the daily patterns required to achieve their body composition goals. They’re also more likely to experience frequent episodes of overeating due to an inability to resist cravings (impulsiveness) and regulate their behavior during periods of sadness and anger. 

To bring this to a close, conscientiousness and neuroticism seem to work on opposite ends of the spectrum for weight loss, while extraversion, agreeableness, and openness appear to play trivial roles as evidenced by inconsistent findings within the scientific literature. As such, determining an individual’s baseline levels of conscientiousness and neuroticism may prove useful for predicting their dietary success and for individualizing their dietary strategy.

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