According to the article “The Mental Strain of Making Do With Less” by Sendhil Mullainathan, dieting is good for the waistline, but bad for mental capacity. It turns out that all the effort people put into trying to maintain their diet takes up precious brain power and makes them a bit distracted and a bit stupid.
And, it’s not because of a lack of brain food:
One particularly clever study went further. It tested how dieters and nondieters reacted to eating a chocolate bar. Even though the bar provided calories, eating it widened the bandwidth gap between dieters and nondieters. Nondieters ate and moved on, but dieters started wondering how to make up for the calories they had just ingested or, even more fundamentally, pondered, “Why did I eat the bar?”
So, mental capacity isn’t necessarily being affected physiologically. Instead, dieting has psychological effects. As the author put it: “There is a paradox here: diets create mental conditions that make it hard to diet.”
The really interesting thing about this article is that it didn’t stop there and just leave it as a diet article. The author extended that logic and the research to show us that this kind of effect can be seen in a lot of other deprived populations. The poor, for example:
Some people argue that the poor make terrible choices and do so because they are inherently less capable. But our analysis of scarcity suggests a different perspective: perhaps the poor are just as capable as everyone else. Perhaps the problem is not poor people but the mental strain that poverty imposes on anyone who must endure it.
So, poor people are in a vicious circle of making bad choices that prevent them from getting ahead and being deprived so that they can’t make better choices.
They also looked at some farmers (in a community where the farmers are paid at harvest and are struggling to make ends meet by the time harvest comes around the next year):
We measured farmers’ mental function — on what psychologists call fluid intelligence and executive control — one month before and one month after harvest. And the effects were large: preharvest I.Q., for example, was lower by about nine to 10 points, which in a common descriptive classification is the distance between “average” and “superior” intelligence.
According to the author, missing a full night of sleep has the same effect.
So, research about people trying to diet gives us a new perspective on poor people and gives us another reason to give them a little extra understanding.
Bandwidth scarcity has far-reaching consequences, whether we are talking about poor farmers or affluent dieters. We all use bandwidth to make decisions at work, to resist the urge to yell at our children when they annoy us, or even to focus on a conversation during dinner or in a meeting. The diversity of these behaviors — combined with the size of the measurable effects — suggests a very different way to interpret the choices and behaviors of the poor.
Of course, for poor people, the only way out is to get a little help or a little luck. Dieters, on the other hand, can use this research to their advantage. If you really want to diet, stick with one that’s easy and takes less mental capacity to follow:
…economizing on bandwidth — can be used in dieting. Take the Atkins diet, which effectively bans many foods, including bread and a lot of desserts. A ban is less complex than the trade-offs and calorie accounting required by many other diets. While all diets require self-control, Atkins requires less thinking. This might explain its popularity, and even its effectiveness: a recent study shows that people persist longer with diets that require less thought.
That said, I tend to avoid diets. The science isn’t behind them, especially not ones where you completely restrict certain food groups (your brain needs carbs for fuel!). They can have great short term effects, but unless you make a lifelong change (i.e., diet forever), they don’t have long term success. Also, you’re sending your body mixed messages if you start a new diet and increase your fitness at the same time. I know that’s what the magazines are telling you to do, but it’s a silly idea. Essentially, you’re telling your body, “Hey, I’m going to make you work harder, but I’m also going to give you less fuel.” Where’s the logic in that?