Research Review: Calories vs. Personality: What’s More Important For Weight Loss?

Thankfully, the “too many calories” theory of obesity is dead or at least in sharp decline with the realization that there is a lot more going on. Frequent meals, higher protein intake, more exercise, timing of good carbs and all that good info from JB are all important for weight loss and staying healthy.

But what if you’re skinny or overweight because of your personality? Then what?

It got me thinking. Am I lean because of a personality quirk? For some reason, that idea bothers me. I don’t know why. It shouldn’t. The idea that personality would affect your life isn’t that shocking. Really, it makes perfect sense.

For example: sky divers. What’s the personality of somebody who sky dives? Worried all the time? Pessimistic? Not likely. Paging all worried, pessimistic sky divers. Anybody? Bueller? Nope, didn’t think so.

Personality affects your life, but as a “hard” scientist dealing with physiology and enzymes, the idea that I’m lean instead of overweight because of a character trait wasn’t something that was on my radar. Then I found this interesting study about personality of obese individuals and how successful they were in a weight loss program.

Sullivan S, Cloninger CR, Przybeck TR and Klein S. Personality characteristics in obesity and relationship with successful weight loss. International Journal of Obesity 2007 31:669-674.

Introduction

I don’t have to tell you that there is an obesity epidemic in North America. About 45% of women and 30% of men are trying to lose weight right now.¹

Over the years there have been several studies looking at personality and obesity, but the results contradicted each other. Thus, researchers tried to get some better data by using a new questionnaire: the Temperament and Character Inventory (TCI).

The researchers asked three main questions:

1. Are there personality differences between lean and obese people?
2. Are there personality differences between obese people looking for weight loss methods and obese people who are not?
3. Are there personality differences between obese people who lost weight with behaviour therapy and obese people who did not?

Methods

There were a lot of people in this study (503), which is usually the case in questionnaire-based studies such as these, both because it’s possible to get many people to fill out questionnaires, and because researchers need a large number for meaningful analysis.

The breakdown went like this:

• 264 people were considered lean (Body Mass Index, or BMI of 18.5-24.9)
• 56 obese people (BMI ≥ 35), recruited from the general public
• 183 obese people (BMI ≥ 30), recruited from the Washington University Weight Management Program (WUWMP)

Researchers asked all of the participants a series of questions that looked at “seven dimensions of personality”: novelty seeking, reward dependence, harm avoidance, persistence, self-directedness, self-transcendence and cooperativeness.

Results

Lean and obese personality characteristics

So what did they find?

They found differences in persistence and self-directedness personality traits. Turns out that the obese group had lower persistence and self-directedness scores, meaning that they were more likely to give up easily, to be modest, inactive and have habits that were incongruent (inconsistent) with their long term goals. Fairly intuitive, right? Yup. Nothing too surprising there.

There is one more difference: novelty seeking. Obese individuals had higher novelty seeking scores. But I’m lean and seek novelty. I’m no bore. Really I’m not.

Higher novelty seeking surprised me and offended me. It didn’t seem to add up. I thought of myself and all my friends who are lean. We like adventure. We’re off hiking, biking, sailing – basically any activity you could think of, so how can we have lower novelty scores?

Participant in Vancouver Island's annual Naked Bungee Jump for charity. Likely high scorer on novelty seeking behaviour.

Well, if you look at how the researchers define “novelty seeking”, things became clearer.

Novelty seeking includes being exploratory, curious, and enthusiastic, but it also includes being impulsive, easily bored, disorderly, and trying to avoid monotony. As much as I’d like to think I have high novelty seeking characteristics, I’ve realized how much I like order and routine.

I enjoy my weekly schedule with “adventure” planned ahead of time. I welcome order — and dare I say monotony — from the regular Saturday morning grocery trips to the ritual of packing my food for the next day. With all that in mind, I guess being lean could translate into lower novelty seeking. Who knew?

Obese: Those in a weight loss program compared to those not in a weight loss program

No surprises here. Those in a weight loss program had higher reward dependence (dedicated and dependent) and cooperativeness (social tolerant, helpful and, constructive). If you were to sign up for group weight loss then chances are you are going to be more likely to a) need other people and b) be more cooperative with them.

Obese: What personality is successful at weight loss?

So what separated the people who successfully lost weight (≥10% of their initial weight in 22 weeks) from the unsuccessful (<5% of their initial weight)? Novelty seeking. Again.

Those with high novelty seeking were unsuccessful. Just as the in the lean versus obese comparison, it seems that those with high novelty seeking characteristics were more likely to have problems controlling their weight. The researchers suggest that obese individuals eat to combat boredom because of their novelty seeking personality.

I have a different take based on my own experience and people I’ve come across. If I don’t plan what I’m going to eat, if I don’t grocery shop, if I don’t cook, then I’m going to eat things that aren’t nearly as good for me than if I did. I don’t think boredom is the whole story. I think lack of structure and order associated with “novelty seeking” also leads to unhealthy food choices causing weight gain. If you’re big into novelty, then I don’t see you interested in working out regularly.

Our conclusions

Looking at weight loss and obesity from a completely different vantage point gives us some fantastic new tools. Yes, it’s important to know what you need to do to lose weight and be healthy, but you also need to know what behaviours prevent you from doing those things.

It gives the obesity epidemic a completely new angle. Has fast food and the like enabled novelty seekers to get a wide array of bad food at a drop of a hat? What did novelty seekers do fifty or a hundred years ago? Were there fewer “novelty seekers” or was it that bad food wasn’t easily available? Food for thought, if you’ll pardon the pun.

1. Serdula MK, Mokdad AH, Williamson DF, Galuska DA, Mendlein JM, Heath GW. Prevalence of attempting weight loss and strategies for controlling weight. JAMA. 1999 Oct 13;282(14):1353-8.