Personality and obesity

As I have asserted in earlier posts, personality is partly genetic, partly malleable (let’s say 50/50 for the sake of simplicity). Hence, one cannot blame oneself for every negative outcome or behavior, but still to some extent a person can be changed – hopefully in the right direction.

For instance, a person can learn to be more extrovert, conscientious, agreeable and less neurotic; and a too agreeable person – someone who might be used by other people due to a complete lack of cynicism – can learn to be slightly more antagonistic and calculating.

Personality traits can often be linked to the so called Big Five personality factors: Openness, Conscientousness, Extraversion, Agreeableness, and Neuroticism. In addition, there are of course other important characteristics such as the Dark Triad (narcissism, Machiavellianism and psychopathy). However, in the current post I will only focus on the Big Five and their links to obesity, or adiposity.

As substantial research indicates, personality traits are related to people’s tendency to gain weight. The research article “Personality and Obesity across the Adult Lifespan” (2011) stresses the significance of personality traits for obesity:

Societal shifts in food quality, quantity, and availability are certainly major contributors to this recent increase in obesity. Yet, many other factors are also implicated in weight control. In particular, personality traits are consistently associated with the controllable behaviors that lead to obesity (Provencher et al., 2008) and personality has an effect on adiposity even after controlling for known demographic and genetic influences (Terracciano et al., 2009). Most studies of personality and weight have been cross-sectional; long-term longitudinal studies are needed to test how personality is associated with weight change across the adult lifespan.

The authors also emphasize the importance of avoiding obesity for a variety of reasons – health, individual well-being, as well as economic and social status:

Body weight is a fundamental individual difference variable that has a pervasive effect on nearly every aspect of our lives. Although most commonly implicated in physical health, adiposity contributes to a variety of psychological processes, such as well-being, identity formation, and person perception. Overweight individuals are prone to depression (Luppino et al., 2010), have poor body image (Schwartz & Brownell, 2004), are evaluated negatively by others (Crandall, 1994), and are ascribed traits based on their body size (Roehling, Roehling, & Odland, 2008). In fact, just being associated with someone who is overweight can lead to negative evaluations (Hebl & Mannix, 2003). As such, body weight contributes to how we understand ourselves, how we see others, and how others see us.

As far as earlier studies indicate, Conscientiousness is the most consistently related to overweight of the Big Five. More conscientious people are less likely to be obese and the other way around. This has got to do with one of its corresponding main characteristics, self-discipline:

The traits within the Five-Factor Model (FFM) of personality, Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness, have been linked to health behaviors and outcomes in general (Friedman, 2008; Goodwin & Friedman, 2006; Ozer & Benet-Martínez, 2006) and to abnormal weight in particular (Brummett et al., 2006; Chapman, Fiscella, Duberstein, Coletta, & Kawachi, 2009; Terracciano et al., 2009). Of the five traits, Conscientiousness is the most consistently associated with adiposity. Across different personality measures, populations, and both self-reported and clinician-assessed weight, conscientious individuals have lower adiposity (Brummett et al., 2006; Chapman et al., 2009; Roehling et al., 2008; Sullivan, Cloninger, Przybeck, & Klein, 2007; Terracciano et al., 2009). In particular, the order and self-discipline facets of Conscientiousness are strongly associated with weight (Terracciano et al., 2009). Presumably, those who score higher on Order and Self-Discipline are leaner because they are organized and stick to their diet and meal schedule. The lifestyle choices of individuals high in Conscientiousness likely contribute to their healthy weight. These individuals, for example, are physically active (Rhodes & Smith, 2006), restrain from binge eating and drinking (Rush et al., 2009), and are less likely to have disordered eating (Bogg & Roberts, 2004).

Another important notion is that weight is not static – it is misguided to put oneself into everlasting categories. The important thing is to change the ‘eventual fact’ that one has to gain fat weight over time in one’s life span:

For most people, weight is not static, but fluctuates over time. As individuals age, their metabolic needs decrease, but their energy intake typically remains constant or increases (Bosy-Westphal et al., 2003; Elia, Ritz, & Stubbs, 2000). As a result, until old age, adults tend to gradually gain weight as they age. Similar to weight at any one given point in time, there are considerable individual differences in the extent to which BMI fluctuates across the lifespan.

The general conclusion:

Neuroticism and Conscientiousness are both associated with the health-risk behaviors that contribute to abnormal weight. Individuals high in Neuroticism and low in Conscientiousness are more likely to smoke (Terracciano & Costa, 2004), abuse drugs (Terracciano, Löckenhoff, Crum, Bienvenu, & Costa, 2008), be physically inactive (Rhodes & Smith, 2006), and binge eat and drink (Rush et al., 2009). Consistent with these more recent studies, a meta-analysis found that Conscientiousness correlated negatively with health behaviors that are among the leading behavioral contributors to mortality, including disordered eating, physical inactivity, alcohol and drug use, and smoking (Bogg & Roberts, 2004). Individuals high in Neuroticism, in addition to their other health-risk behaviors, tend to be overly concerned with their shape and weight and, despite their attempts at restraint, tend to lose control over their food intake (Provencher et al., 2008). One outcome of these maladaptive cognitive and behavioral patterns is difficulty with weight regulation.

So if someone has a problem with binge eating, obesity and/or fast fat weight gains, it may important to try to be less neurotic (easier said than done for many who suffer from depression or anxiety disorders) and more conscientious. Perhaps a well-planned and consistent diet schedule with the aim to lose weight over time may be a very wise investment – and even to help save money in the long run.