A fat tax for Ireland?

The government is said to be considering introducing a “fat tax” for Ireland, following the introduction of one in Denmark, as a way of tackling the increase in obesity. It has already prompted some debate, for example here.

It is also being discussed in the UK and the Institute for Fiscal Studies has just published some thoughtful reflections on it, written by Rachel Griffith & Martin O’Connell, drawing on their recent Fiscal Studies paper. Let us hope we have some similarly informed contributions in Ireland.

Peer effects and fitness

This paper addresses whether fitness is contagious arising from recent claims that such peer or contagion effects may partly explain the increase in obesity. It is worth noting that the data is drawn from students at the US Air Force Academy, a very selective institution with a generally pretty fit bunch of people. It seems doubtful that this data will allow one to identify anything about obesity in the population.

Is Poor Fitness Contagious? Evidence from Randomly Assigned Friends
Scott E. Carrell, Mark Hoekstra, James E. West
NBER w16518
The increase in obesity over the past thirty years has led researchers to investigate the role of social networks as a contributing factor. However, several challenges make it difficult to demonstrate a causal link between friends’ physical fitness and own fitness using observational data. To overcome these problems, we exploit data from a unique setting in which individuals are randomly assigned to peer groups. We find statistically significant peer effects that are 40 to 70 percent as large as the own effect of prior fitness scores on current fitness outcomes. Evidence suggests that the effects are caused primarily by friends who were the least fit, thus supporting the provocative notion that poor physical fitness spreads on a person-to-person basis.

Obesity and Hyperbolic Discounting

A recent paper  in the Journal of Consumer Policy (subscription required) considers the usefulness of the hyperbolic discounting concept in the targetting of obesity policy.

Abstract: Efforts to use nutrition education to combat the growing obesity problem in the USA have been largely unsuccessful. One possible reason for the persistence of the obesity problem is the presence of consumers who discount hyperbolically. To counter this phenomenon, sophisticated agents may try to employ commitment devices to protect long–term health goals from short–term consumption decisions. This study uses data from the Continuing Survey of Food Intakes by Individuals to examine the impact of hyperbolic discounting and use of commitment devices on individuals’ caloric consumption. The results suggest that obese dieters display behavior consistent with hyperbolic discounting.

Growing up in Ireland: obesity amongst 9 year olds

I have been looking at the Key Findings for the Growing up in Ireland data (9 year olds). There is lots of interesting information there. One thing that caught my eye was the extent of obesity:
Apparently 26% are overweight or obese. The figure for girls is 30%. This is much higher than I would have expected (never having studied the topic) & seems pretty alarming. Does anyone know how this compares internationally?
The incidence is also much higher amongst lower SES groups.

http://www.growingup.ie/index.php?id=62

Genetic markers as instrumental variables

This looks pretty interesting, a nice combination of econometrics, genetics & epidemiology

Genetic Markers as Instrumental Variables:An Application to Child Fat Mass and Academic Achievement
Stephanie von Hinke Kessler Scholder, George Davey Smith, Debbie A. Lawlor,Carol Propper,Frank Windmeijer

The use of genetic markers as instrumental variables (IV) is receiving increasing attention from economists. This paper examines the conditions that need to be met for genetic variants to be used as instruments. We combine the IV literature with that from genetic epidemiology, with an application to child adiposity (fat mass, determined by a dual-energy X-ray absorptiometry (DXA) scan) and academic performance. OLS results indicate that leaner children perform slightly better in school tests compared to their more adipose counterparts, but the IV findings show no evidence that fat mass affects academic outcomes.

Protecting Consumers

Becker and Posner both address the creation of the Consumer Financial Protection in the US. This agency emerges from the Obama administration partly in response to the arguably ill-informed decisions made by financial consumers during the last 10 years, and is heavily grounded in the behavioural ideas of Thaler and Sunstein. Posner argues that the current wave of regulation is excessive and gives the examples of smoking health warnings back in the 1960s and food safety inspections as legitimate forms of consumer protection. The difference between these and the financial decision making case, according to Posner, is that the market failure is clear in the case of both smoking and food safety legislation and the potential remedies are clear and welfare enhancing. He argues that potential market failures from poor financial decision making are harder to demonstrate and to remediate, leading to poorly targeted and expensive government regulation. He argues for obesity as a case where there may be a case for intervention arising from the high health-care cost externality resulting from elevated population chronic illness prevalance.

Becker is even tougher on the bill.

"I believe that a Consumer Financial Protection Agency will hurt rather than help consumers. Despite the claim that ignorance induced many consumers with few resources to buy houses during the boom, consumers who bought a house then with almost no down payment and low interest rates were not displaying ignorance, but good sense." 


He makes the classical argument against behavioural intervention.


"In the vast majority of cases, consumers, even those with little education, know their own interests far better than government officials know them."

Becker is also far tougher on obesity externality arguments than Posner, arguing that they distort consumer decisions. He leans on the side of allowing insurers to price obesity into insurance costs, a debate that would be worth having here. 

Would you like a box with that?

A noticeable feature of dining in American restaurants (well maybe not the posh places that I can't afford) is that they offer you a box to take your left-overs away in. You can often get a second meal out of this (tonight for example) unless, of course, you forget to retrieve it and your car smells of curry for a month. No chance of that happening in Ireland or the UK. I think I saw some unfortunate American ask once in Dublin only to be sniffily refused.
So is it a "good thing"? Well the option of a box means that you get what you pay for or at least the gap between the value of what you pay and the value of what you consume is smaller. The cost of the box is probably small so an efficiency gain, for sure.
Or is it? I have this niggling feeling that there may be a downside. Without the box, you have an incentive not to over-order. If we assumed that people don't know how much they want to eat or how much is good for them (otherwise why is there an obesity epidemic) then its less clear to me that having this option is welfare improving.

Minimum wages & obesity

The paper below ties together two important but seemingly disparate topics minimum wages and obesity. The argument is that in the US the federal minimum wage fell between 1968 and 2007 thus making fast food cheaper and this should have lead to more obesity.

They find "... that a $1 decrease in the real minimum wage was associated with a 0.06 increase in BMI. This relationship was significant across gender and income groups and largest among the highest percentiles of the BMI distribution. Real minimum wage decreases can explain 10% of the change in BMI since 1970. We conclude that the declining real minimum wage rates has contributed to the increasing rate of overweight and obesity in the United States."

The impact of minimum wage rates on body weight in the United States
D Meltzer, Z Chen
http://papers.nber.org/papers/w15485

BMI and Health Status

The flaws of using body mass index as a measure for overall health status are apparent. It is a 19th century technique which ignores the distribution of both muscle mass and bone in the body. In addition, the relationship between and health status is likely to be non-monotonic, most likely quadratic.

However, the use of BMI in research does have some advantages. It is very quick and inexpensive to measure. In addition, it is plausible that BMI is a strong indicator of individual's health preferences and behaviours. Also, BMI is a continuous metric. Therefore, if we choose to use BMI as a proxy for health status we do not have to constrict ourselves to discrete choice statistics when estimating the conditional distribution for 'health'.

The way in which BMI is used in estimation strategies needs to be redefined. BMI's definition of 'overweight' is outdated, and does not recognise that the population has become bigger, stronger and healthier in the last 150 years. Bone structures with greater density and increased muscle mass are not the same as body-fat increases. They are health promoting, not health deterring. Obesity is rising, and the negative health effects are undeniable. However, the shift from 'normal' BMI to 'over-weight' BMI and the negative health outcomes are dubious. For example, Romero-Corral et al. show how coronary deaths amongst 'over-weight' BMI cases are lower those individual's defined as having 'normal' BMI.

So how should the eager researcher approach this issue? In my opinion, we should accept that the bounds defined by the BMI scale are now invalid and have no basis acting as a proxy for overall health. The mean of health and BMI has shifted in over the last century, however I would argue that the new mean indicates improvements in health - strongly supported by life-expectancy increases, height increases, etc. - and that it is the deviations away from this mean which give a more precise measure of overall health status. One estimation strategy which maintains the continuous properties of this metric would be to measure BMI in z-scores (deviations from the mean controlling for the size of the standard deviation) or the z-score squared.

The Effect of Child Weight on Academic Performance: Evidence using Genetic Markers

von Hinke Kessler, Scholder, S
This paper examines the relationship between children’s weight and academic outcomes using genetic markers as instruments to account for the possible endogeneity of body size. We use medically assessed measures of body size which are more appropriate than the generally used BMI measures. OLS results indicate that leaner children perform better in school tests compared to their heavier counterparts, but the IV results, using genetic markers as instruments, show no evidence that fat mass affects academic outcomes. We compare these IV results to those using the instruments generally adopted in this literature. We show that the results are sensitive to the instrument set and argue that several of the commonly used instruments do not meet the exclusion restrictions required of a valid instrument.

http://d.repec.org/n?u=RePEc:yor:hectdg:09/25&r=edu

Being Fat is Your Own Fault

Interesting debate on obesity. I like the way the Professor makes the distinction between over-fat and overweight.

Childhood Obesity and the Internet

I gave a presentation to a Dail group charged with implementing the Obesity taskforce this week.

The topic of the presentation was on the role of the Internet in childhood obesity. I made the point that internet advertising broadly defined was changing fundamentally the task for those interested in controlling the messages being delivered to children and adolescents in the area of diet and physical activity.

There are strong reasons to begin to look at the role of the internet in childhood obesity. As well as advertising, the increasing amount of time spent by children online is itself contributing to sedentarism.

Even a brief google search for this topic will reveal to you a whole ecology of food-related websites, ranging from bebo pages for popular foods like Skittles to things like "McWorld" where kids can play video games.

The extent to which online social networks condition diet and physical activity is something for which there is little evidence. Also, we know very little about the nature and type of messages that children glean from the web about diet and physical activity and how this alters their risk perception, forms their identity and conditions their self-control.

It is clear however that companies are experimenting vigorously with the use of the net and are working all the available channels and the connections between them. This is changing fundamentally the relevance of existing advertising restrictions and needs to be thought about actively in a way that has not yet been done.

This is an area for which policy needs to emerge and develop. At the very least, a new set of social norms needs to emerge quickly about what companies should and should not do with respect to online activities. Also, government agencies as well as parents and voluntary groups need to think about using technologies such as adsense and related technologies to counteract the messages being beamed to kids by marketers and by other kids.

For example, if you do a basic google search for things like bulimia you will find a string of advertisements for treatments. It raises the question as to whether government agencies should be trying to actively intervene in these messages through their own advertising.

I wrote a report a few years ago about the scope of volunteering in Irish sport. One form that volunteering may need to take on is to attempt to turn the web into something that promotes or at least is neutral toward physical activity. This may mean those who believe in physical activity and healthy eating as positive forces for children actively blogging and pointing out behaviour of groups who are using the web in ways that flout social norms about how we should persuade children.

Public health video

For a public health video on obesity see "Brave Heart (Mutiny in the Cardiovascular System)"
http://www.youtube.com/watch?v=gI6KhUrKpN0

How you could be eating more and not know it

Shari Roan from the LA times reviews some of the key studies which aim to explain nonconscious influences promoting calorie intake:

"People can be influenced to eat unhealthful food, or more food than they should, without even realizing it.

* Advertising matters. One study, published last year in the Journal of Consumer Research, found that people think they are eating healthfully if it's advertised that way. Researchers had people eat Subway meals that contained the same amount of calories as a McDonald's meal, but the people estimated that the Subway meal contained 35% fewer calories.

* Eating is automatic. A 2004 study in the journal Appetite showed that people who are served bigger portions will eat more. Men given large bags of potato chips ate triple the number of chips -- an extra 311 calories -- compared with men given a small bag of chips.

* Visual cues prompt eating. A 2004 study in the Annual Review of Nutrition found that people ate 69% more jelly beans when they were offered in a mixed assortment than a group offered jelly beans sorted by color.

* The setting matters. A 2005 study in the journal Personality and Social Psychology Bulletin found that the more pleasant the environment, the more people will eat. People shown a picture of a smiling person poured more of a drink, drank more and rated the drink more favorably than people shown pictures of a frowning person.

* Portions direct eating. A 2003 study in the American Journal of Clinical Nutrition found that doubling the size of an entree increased overall food intake 25%. The consumers did not compensate for the bigger entree by decreasing the intake of other food on their plates.

* Other people influence eating. A 1992 study in Physiology & Behavior found that food consumption increased 28% when one other person was present and 71% when six or more companions were present.

* Eating is contagious. A study published last year in the New England Journal of Medicine showed that obesity can spread through social networks. A person's chances of becoming obese increased 57% if he or she had a friend who became obese in the same time period. If one sibling became obese, the chance that the other would become obese increased 40%.

* Marketing matters. Several studies published in the 1970s and 1980s show that doubling the shelf space of an item in a grocery store increases sales of the item as much as 40%."

NBER -- Body Composition and Wages

URL: http://d.repec.org/n?u=RePEc:nbr:nberwo:13595&r=hea
This paper examines the effect of body composition on wages. They develop measures of body composition “ body fat (BF) and fat-free mass (FFM) “ using data on bioelectrical impedance analysis (BIA) that are available in the National Health and Nutrition Examination Survey III and estimate wage models for respondents in the National Longitudinal Survey of Youth 1979. Their results indicate that increased body fat is unambiguously associated with decreased wages for both males and females. This result is in contrast to the mixed and sometimes inconsistent results from the previous research using body mass index (BMI). They also find new evidence indicating that a higher level of fat-free body mass is consistently associated with increased hourly wages. Finally they present further evidence that these results are not the artifacts of unobserved heterogeneity and show their findings robust to numerous specification checks and to a large number of alternative BIA prediction equations from which the body composition measures are derived. This work addresses an important limitation of the current literature on the economics of obesity. Previous research relied on body weight or BMI for measuring obesity despite the growing agreement in the medical literature that they represent misleading measures of obesity because of their inability to distinguish between body fat and fat-free body mass. Body composition measures used in this paper represent significant improvements over the previously used measures because they allow for the effects of fat and fat free components of body composition to be separately identified. The work also contributes to the growing literature on the role of non-cognitive characteristics on wage determination.

Internal Disinhibition Predicts Weight Regain Following Weight Loss and Weight Loss Maintenance

The disinhibition scale of the Eating Inventory predicts weight loss outcome. Exploratory factor analysis of the disinhibition scale was conducted on 286 participants in a behavioral weight loss trial (TRIM), and confirmatory factor analysis was conducted on 3345 members of the National Weight Control Registry (NWCR), a registry of successful weight loss maintainers.

In TRIM, internal disinhibition significantly predicted weight loss at 6 months (p = 0.03) and marginally significantly predicted weight loss at 18 months (p = 0.06), with higher levels of internal disinhibition at baseline predicting less weight loss; external disinhibition did not predict weight loss at any time-point. In NWCR, internal disinhibition significantly predicted one-year weight change (p = 0.001), while external disinhibition did not. These results suggest that it is the disinhibition of eating in response to internal cues that is associated with poorer long-term weight loss outcomes.

Niemeier et al. (2007)

Mindless Eating

There are numerous studies addressing the question of how aware people are of the food-related decisions they make and how the environment influences these decisions. This study is nice in its simplicity and the magnitude of the effect found. Wansink & Sobal (2007) show that people underestimated the number of food-related decisions they made—by an average of more than 221 decisions! Participants overate 31% more food as a result of having been given an exaggerated environmental cue (such as a large bowl). Of those studied, 21% denied having eaten more, 75% attributed it to other reasons (such as hunger), and only 4% attributed it to the cue. The authors suggest that we are aware of only a fraction of the food decisions we make and that we are either unaware of how our environment influences these decisions or we are unwilling to acknowledge it.

Does Obesity Hurt Your Wages More in Dublin than in Madrid? Evidence from ECHP

BEATRICE D'HOMBRES,,GIORGIO BRUNELLO

IZA Discussion Paper No. 1704

Abstract:
We use data from the European Community Household Panel to investigate the impact of obesity on wages in 9 European countries, ranging from Ireland to Spain. We find that the common impact of obesity on wages is negative and statistically significant, independently of gender. Given the nature of European labor markets, however, we believe that a common impact is overly restrictive. When we allow this impact to vary across countries, we find a negative relationship between the BMI and wages in the countries of the European "olive belt" and a positive relationship in the countries of the "beer belt". We speculate that such difference could be driven by the interaction between the weather, BMI and individual (unobserved) productivity.

Vertical Workstations

Walking while you work might help fat people shed as much as 66 pounds - or nearly five stone - in one year, according to a study published today.

See here.


Guinea pig: Roger Highfield, science editor of The Daily Telegraph, lost nine pounds on the treadmill