Obesity: Class Warfare, Imperfect Information... or both?

Saw this on CNN today: Poor and fat: The real class war, by L.Z. Granderson. Some figures from the article:

Ground beef that is 80/20 is fattier but cheaper than 90/10. Ground turkey breast is leaner than the other two but is usually the more expensive. And many of us can't even begin to think about free-range chicken and organic produce -- food without pesticides and antibiotics that'll cost you a second mortgage in no time at all.
...The American Journal of Clinical Nutrition recently published a study that found $1 could buy 1,200 calories of potato chips but just 250 calories of vegetables and 170 calories of fresh fruit. And it is also true that Mississippi, the poorest state in the country, is also the fattest.
In fact, the five poorest states are also among the 10 fattest, and eight of the 10 poorest states are also among the 10 with the lowest life expectancy.
I guess one could dismiss this as one big coincidence, but is it also a coincidence that half of the top 10 states with the highest median incomes are also in the top 10 in life expectancy?

I would interpret Granderson's argument as: low-income leads to unhealthy foods leads to fat (leads to more healthcare spending and even lower incomes). Looking at calorie counts compared to food prices does seem to support that. However, bringing some micro theory into the discussion complicates this causal story somewhat.

We can quantify the effect of income on food choices through this simplified model. Imagine two different families, both trying to fill a calorie requirement of 2000, but the low-income family has a food budget of $3 and the high-income family has a food budget of $10.

After plugging numbers into the formula above, the high-income family buys only 0.3 servings of potato chips and 9.7 servings of fruit, while the low-income family gets about 1.4 servings of potato chips and 1.6 servings of fruit.

The same intuition is expressed graphically below. Purchasing decisions are represented by points where the red and blue lines cross.

So far, so good: as one would expect, the high-income family buys more fruit and less potato chips than the low income family. One problem for this example, though, is that neither of these families will be gaining any weight!

If people only eat the necessary calories to keep an even weight, it won't matter whether their income is high or low. They'll just adjust their purchasing choices to get the right amount of calories. A dietitian might frown on you for eating chips as a snack instead of fruit, but as long as your consumption of chips is small, it won't necessarily cause you to gain weight.

It takes some extra assumptions to model over-eating. Maybe there's some property of potato chips that causes people to eat too much of them, i.e. what if someone buys potato chips thinking that a $1 serving will be 1200 calories, when it's actually equivalent to 1600 calories? Keeping with the numerical example above, the rich family would overeat by about 120 calories and the poor family by 560 calories.

It's only imperfect information or self-control problems which make food choices cause weight-gain. If we assume that low- and high-income types have exactly the same sort of bounded information, we'll find that the rich gain less weight, because their greater resources have them purchasing less unhealthy food to begin with.

This story gets even more pessimistic if there is some difference between low- and high-income people's capacity to overcome imperfect information. It might be that the poor have less time/energy to research and craft their diet than the rich do, so they are more prone to mistakes. Additionally, there could be some personal attribute - an impulsive nature or low conscientiousness - which both causes someone to have low income and also makes diet control more difficult.

While the costs of obesity are worth addressing given their heavy contribution to public healthcare spending, as Granderson rightly observes, the lens of class warfare isn't the best for understanding the problem.

Ultimately, to prevent obesity people need more incentive to monitor their own health. For me, it's knowing that on the current trajectory of public health care spending, there probably won't be any money left by the time I'm old and infirm. It doesn't entirely surprise that current beneficiaries of public health care are not too concerned about solving this spending problem for the rest of us (morbid fact: about a third of health care spending goes to patients in their last year of life). Which class is under attack, and which class is attacking anyway?

Maybe the obesity problem will resolve itself as young people make the calculations and figure they will likely be on their own, in terms of medical care, by the time it is most necessary. Or maybe the lure of potato chips is simply too great for us as a nation and will lead to our fiscal undoing.

I Have No New Years Resolutions.

The New Year is a nice time, symbolically, to make a big change in life but practically it almost never works out that way. From a Boston Globe article, I learned that 80% of New Years resolutions are broken. Frankly, I'm surprised that as many as 20% are accomplished! People don't change much on the eve of December 31 to the morning of January 1 (perhaps except for the addition of a hangover) so I suspect much of the 20% accomplished are trivial ("remember to call my mom on her birthday this year") and require single actions, not sustained effort.

Resolutions are puzzling from both an economic and psychological perspective. To an economist, there's no reason why one day should be intrinsically more favorable than another to make a positive life change. If drinking less or exercising more would be a good idea, why wait until January 1st to start doing it? On the other hand, a psychologist might wonder why people set themselves up for failure so often. If 80% of resolutions ultimately amount to lying to yourself, why persist in encouraging such a mentally unhealthy activity?

The real question: if most resolutions would be good things to accomplish, why are people so bad at keeping them? It's easy to just dismiss New Years resolutions as "cheap talk" which people utter in order to sound socially acceptable and make themselves feel better, with no intent of actually following through. But, I think there's a little bit more to it than that.

In their book, Willpower: Rediscovering the Greatest Human Strength, Roy Baumeister and John Tierney offer a pretty good explanation for why New Years resolutions have such a short shelf-life. When someone creates a list of challenging self-improvement tasks, they are probably very optimistic about their future state of mind. But, realistically, we only have so much willpower to divide between different goals that require self-control. Willpower, in this regard, is somewhat like a muscle: when it is used lots in a short span of time it becomes fatigued, so later acts of self-control are more difficult. Creating a list of resolutions is like weight-lifting beyond the mind's capacity; it can't dedicate enough mental power to accomplish all the goals at once, so in the end none of them are met. As a result, creating a big list of dramatic changes is one of the least effective ways to actually modify your own behavior.

A better strategy is to choose one area that seems most important and focus on moderate improvements. Also like a muscle, willpower can become stronger when exercised. Picking reasonable goals gives a sense of accomplishment when they are completed, making it easier to stick with other changes in the future. In other words, build up capacity slowly to avoid a painful sprain of the willpower muscle (although if I stretch this analogy much further, I might suffer a tear in my credibility). Introducing the concept of willpower to economic thinking means we don't have to dismiss failed self-improvement projects as mere cheap talk, and can instead look more realistically at the human mind and its practical limitations.

"Fat Head": why fat is good and nutritionists are wrong.

My role model.

I try to blog on topics within my field - economics - which is usually easy, because economics encompasses almost everything. However, I recently watched a health documentary which inspired me to brave the big, scary world of health and nutrition. Written and directed by former health writer and comedian Tom Naughton, "Fat Head" is a must-watch for everyone, especially those who liked and/or took seriously Morgan Spurlock's "Supersize Me."

Available on Netflix and Hulu as well for sale off the creators website, "Fat Head" is a quick, fun and informative video. However, for those who want the factual gist of it without the cheesy (but amusing) commentary and animations, I present this partially-digested version of the food documentary, broken into three main chunks for easy consumption.


1. The numbers in "Supersize Me" don't add up. In the movie, Spurlock's nutritionist repeatedly says he's consuming over 5,000 calories per day. Problem is, according to Spurlock's own rules, he only had three square meals per day. Even if he Super-Sized at every opportunity (which he claims not to have done) that still only adds up to a rough 3,600 calories. Where'd the rest come from? He must have added several desserts. If someone stuffs themselves with over twice the calories required for a healthy adult... is it really surprising that they gained weight?

Money Melts the Pounds Away -- an in-depth look at The Biggest Loser outcomes.

No, this is not veiled commentary on my social life.

Obesity is a growing issue in the industrialized world generally and the United States in particular. The science behind obesity is still developing, but the popular culture response has already begun. Reality television, which has previously attempted to resolve our lovelessness, joblessness, and lack of fashion has now begun to confront the ‘American lifestyle.’ 

Television network NBC’s hit reality series “The Biggest Loser” takes a group of overweight individuals and sequesters them in a large housing and gym facility. There, under the oversight of expert personal trainers and medical personnel, they attempt to lose weight as quickly as possible. Taking place within a competitive team setting, at the end of each week the people who lost the least weight risk being eliminated. At stake is $250,000 cash for the winning player and a $100,000 prize for the eliminated player losing the most weight by the finale.

The Biggest Loser's game-show world bears only loose relation to the reality of an average person looking to drop a few pounds. However, its dramatic format and inspiring message have proved a global success, with the creation of Biggest Loser UK, Biggest Loser Australia, and Biggest Winner Arab (to name a few). The American version of the show has produced nine seasons since 2004, with a tenth being filmed as of this writing. 

 

With each contestant’s weight loss announced weekly, this television series provides a wealth of data on weight loss under ideal and controlled conditions. With 6 to 8 daily hours of exercise, a rigidly structured diet organized by top-rate personal trainers along with a strong monetary incentive, participants on The Biggest Loser have every advantage in losing large amounts of weight. Some drop over twenty pounds, or over 5% of their body mass, in a single week. The vast majority go on to change their lives by adopting healthier eating habits and frequent exercise. These results demonstrate weight loss at the absolute limit of human capacity. 

 

While every participant on The Biggest Loser puts in a monumental effort to lose weight, there can only be one winner. Contestants experience different outcomes in weight loss in spite of a generally high standard of effort. There have been many debates in the bio-medical field on whether obesity is caused by genetics, culture, age, or something else entirely, and a consensus has yet to emerge. With its wide demographic variety, The Biggest Loser provides an opportunity to test how these differences impact optimal-scenario weight loss.