New Year's resolutions through delayed gratification

It's that time of the year. That I-will-eat-better-and-exercise-lots time. It's that time when we kick start New Year's resolutions with the best intentions, the best plans, the most motivation. Unfortunately, and I can tell you this from experience, some of us will fail. A recent article published in the journal Obesity sheds light on one important aspect in keeping some resolutions: delayed gratification.

Delayed gratification, as the name implies, refers to the ability to forgo an immediate reward (for example, delicious Cheesy Poofs) for a benefit that will come later (for example, rocking that little black dress). A lot of research shows that the better you are at delaying gratification, the better you do in life in general (you may have heard of the famous marshmallow study). To see if delayed gratification is linked to obesity, a team of researchers set out to test whether children who have a high body mass index (BMI) are less likely to delay gratification.

The researchers looked at data from an educational obesity intervention program. In this program, attended by obese or overweight children along with their siblings (the healthy weight control group), children earn a point if they complete their weekly goals. They then have two choices: either spend that point immediately on a small toy prize (like a pencil) or save the point to use later on a larger prize worth more than one point (like a basketball). The measure of points saved and points spent is thought to be a valid model of delayed gratification. So the researchers looked at the relationship between how many points were saved by a child and that same child's BMI. The results show that a higher BMI is associated with less points saved, meaning the children who were overweight or obese had a harder time delaying gratification.

The strong aspect of this study is that the rewards were not food-related. This allowed the researchers to study delayed gratification as a behavior trait in general, and not specifically as it relates to obesity. However, their sample was fairly small (59 children) and the duration of the study was fairly short (12 weeks). Therefore, it's difficult to say whether delayed gratification plays a role in weight loss.

Overall, the research is relevant in that it suggests that working on delayed gratification (it's possible to "train" to get better at it) may help in obesity interventions. And for all you out there with eat-less-exercise-more resolutions, all I can say is "eyes on the prize"...

Reference: Ability to delay gratification and BMI in preadolescence. (2010) Bruce, AS and al. Obesity [Epub ahead of print].

Light at night, what a fright!

When I picked my paper for this week’s blog, a very recent article published in PNAS, I didn’t factor in that I would write it on Halloween. Now I realize it’s going to seem like some cruel joke: on the one night where people stay up late walking the streets with flashlights and eat candies, I’m writing about the link between light at night and obesity. Wow. If I had tried to pick something more fitting, I couldn’t have done a better job.

We all know obesity is on the rise and there are several reasons to explain the epidemic: increased intake of calories (Double Down sandwich, anyone?), dietary choices (cheezy poofs instead of apples, anyone?) and lack of exercise (reading blogs, anyone?). However, the rise of obesity rates also coincides with an increase in light at night – the artificial lighting that allows us to write blogs late at night and catch up on all other activities we didn’t have time to do during the daytime. The problem is that light is closely tied to our circadian rhythm (the built-in clock that controls our biological processes and our behaviour). When our circadian rhythm is disrupted (an extreme example of this is shift workers), so is our metabolism. Based on this logic, an international team of researchers set out to test whether light at night plays a role in the weight of mice.

The researchers divided their mice into three groups. The control group was housed in the standard light/dark cycle. Another group of mice was housed in a light/dim light cycle (let’s call them the “dim” group). Finally, a third group of mice was housed in a continuously lit room (let’s call them the “bright” group). The mice were housed in these conditions for eight weeks, and during this time, the researchers monitored a number of parameters including body mass, food intake, activity levels, and glucose tolerance (how quickly sugar is cleared from the blood).

The researchers found that all the mice that experienced light at night (both the dim group and the bright group) got significantly fatter than the control mice. What’s more, the dim group and the bright group also exhibited impaired glucose tolerance (this can mean the mice are in a prediabetic-like state). Did the light at night groups of mice eat more (who doesn’t get the munchies when watching a late-night movie)? No. Did they exercise less (who goes for a run at midnight)? Also no. So what happened?

As it turns out, while the two light at night groups of mice ate just as much as the control mice, they ate at different times. Mice are nocturnal animals, and so normally they do most of their eating at night. The mice in the dim group, however, ended up eating over half of their food during the “light” phase. When the mice in the dim group were forced to eat their normal food intake only during the normal (dark) time, they didn’t gain weight. How crazy is that? These results suggest that light at night disrupts the timing of food intake, and this throws the metabolism out of whack.

Anyone who has looked up weight loss tips knows that it’s a good habit to forgo eating past a certain time of night (usually 7 or 8pm) if you want to lose weight. The reason usually given to explain this is that night time food is most often unhealthy and calorie-laden snacks: munchies during a movie, or ice cream after a distressing phone call from the ex-boyfriend. This study suggests there might be something more to this weight loss strategy: it may be all about listening to our biological clock.

Reference: Light at night increases body mass by shifting the time of food intake. (2010) Fonken LK et al. PNAS 107(43):18664-9.

Is Scooby-Doo to blame?

In this age of pre-prepared processed meals and endless hours on Facebook, it’s no wonder kids are getting fatter. In the US, obesity rates have doubled for preschoolers (2-5 years old) and more than tripled for children 6-11 years old. To explain this alarming obesity trend, many blame the accessibility and affordability of fast food. As a graduate student I often relied on cheap take-out to sustain myself. Luckily I quickly discovered that in Vancouver, sushi costs less than a McDonald’s meal, offering an interesting alternative. If my rent didn’t force me to live below the poverty line (hey, this PhD’s got to be worth something, right?), I would have thought this was heaven. In any case, I’m digressing. Cheap fast food is one part of the equation, kids drooling, lifeless, in front of the computer and the television is probably another part. Interestingly, a recent study suggests that another contributor to the obesity crisis is no other than… Scooby-Doo. And Dora. And Shrek.

The researchers were interested in finding out if putting the image of a popular character on the packaging of a product (this marketing ploy is called “character licensing”) is an effective way to sell food to kids. To test this, the researchers studied three foods: graham crackers, gummy bears and baby carrots. The participants in the study, children aged 4 to 6 years old, were presented with two packages of the same food item (for example, graham crackers). The only difference was that one of the packages had a sticker of a cartoon character (Scooby-Doo, Dora or Shrek) on it. The kids were then asked to say if one of the two foods tasted better, and if so, which one. They were also asked which food they would prefer to have for a snack.

So, does it work? Are children that oblivious to this obvious and dubious marketing trick (Scientific Chick challenge: Write a sentence with more than 3 words ending in -ious)? Absolutely. Overall, children perceived the food items with the cartoon on them to taste better than the ones in the plain packaging. This finding was statistically significant for the “junk” food (the crackers and the gummy bears). Not surprisingly, the children also indicated they would prefer the snacks with the characters on the packaging. As it turns out, character licensing is especially effective in children because they lack the ability to understand that the advertisement is meant to be persuasive.

You would think that all you would have to do to solve the obesity crisis is to slap Elmo’s face on broccoli and apples, but the fact that the character licensing experiment didn’t work as well with the carrots suggests this wouldn’t necessarily do the trick. The researchers only studied 40 children, a relatively small sample size to draw out any solid conclusions, but it’s still an interesting finding. I find it a little worrying that cartoon characters can lead to a more positive perception of the taste of junk food. I find it very worrying that food and beverage companies spend more than $1.6 billion per year on advertising for kids. I guess Ramen advertises for grad students and nobody gets worked up about that.

Reference: Influence of licensed characters on children’s taste and snack preferences. (2010) Roberto et al. Pediatrics, 126(1):88-93.