Will Restricing Soda Access in School Cause Children to Lose Weight?

The answer is "no" according to this study just published in the journal ICAN: Infant, Child, & Adolescent Nutrition:​  Here is the abstract:

Background. School policies limiting the availability of sweetened beverages are often considered to be effective interventions for improving children’s diet and weight-related health. This study was designed to examine the effectiveness of the Rhode Island Healthier Beverage Policy in reducing consumption of unhealthy beverages and in producing changes in children’s weight status. Method. Students in 2 public middle schools in Rhode Island completed self-reported measures of dietary intake and were measured for height and weight prior to and 1 year following the implementation of a state-mandated healthier beverage policy. An inventory of beverages available in vending machines after the beverage policy was implemented provided a measure of adherence with the statewide policy. Results. Both surveyed schools demonstrated compliance with the beverage policy (ie, greater than 70% of available beverages complied). Self-reported consumption of sweetened beverages did not change significantly following policy implementation. Neither average BMI percentile for age and gender nor frequency of children in each weight category changed significantly 1 year after the policy was implemented. Conclusions. Although the healthier beverage policy was effectively implemented, it did not result in changes in self-reported sweetened beverage consumption or weight status 1 year later. Additional school policy and individual-level changes appear to be necessary to effect change in weight and dietary outcomes for children.

As I've indicated before​, changes in schools can alter kid's behavior in ways unintended by the policy makers.  And, even when more healthy foods are offered, kids don't have to eat them.

Fat Tax Complications

About four months ago, I gave a talk at a planning meeting of the Institute of Medicine of the National Academies hosted by the CDC​.  The title of the meeting was the "Exploring the True Costs of Food."  Health, nutritional, epidemiological, and environmental experts from all the top Universities were there as were representatives from major livestock industries and food and environmental NGOs.  

The implicit objective of the meeting was to determine factors affecting the "true" cost of food.  As an economist, my initial response to such inquiries is "markets already do that."  Except when there are externalities.  Aside from what seemed (at least to me) some slivers of agreement on a few environmental issues, there was remarkably little agreement between some of the economists in the room and the nutrition/health experts on the extent to which obesity and other diet-related diseases represent an externality.  

I won't rehash the whole debate in one post, but I do want to make reference to one issue that I mentioned several times at the meeting.  ​It is an issue that Robert Murphy discusses in a feature article just released at the Library of Economics and Liberty.  His argument, which relies on work in an American Economic Review article by Bovenberg and Goulder, relates to carbon tax swaps, but it could equally apply to issues like fat taxes.

In short, even if we could agree that obesity and dietary-related diseases represent an externality (and we don't), one would still have to do the really hard work of determining the "optimal" tax.  This hard work is further complicated by the fact that there are myriad distortions in the economy from other taxes, subsidies, and regulations.  Another complicating factor is that an "optimal" tax is not a static measure - it changes constantly with prevailing conditions such that the "optimal" tax at one point in time can actually do more harm than good​ when market conditions change.  Just look at a plot of corn or soybean prices over the past five year and it is quite clear that market conditions can and do change rapidly.  Moreover (and this is one of the key points of Murphy's article), it can't be taken for granted that the revenues from a fat tax would be subsequently used in ways that generate economic benefits that are often presumed by fat tax advocates.  

Here is the second paragraph of Murphy's article:​

Although the thinking underlying the conservative case is correct, there is a potential downside from a carbon tax swap. This negative side effect is rarely mentioned in any but the most technical discussions. It is the "tax interaction effect." A new carbon tax can exacerbate the harms caused by pre-existing taxes, thereby offsetting the potential environmental benefits. What's worse, not only can the tax-interaction effect operate in theory, but also numerical simulations suggest that it might be very large in practice, greatly reducing the "optimal" carbon tax.

​and the last:

Proponents of a carbon tax swap deal are right when they claim that the gross harms of a new carbon tax can be partially offset if its receipts are used to reduce other taxes. However, they typically leap from this true claim to the unjustified conclusion that a revenue-neutral carbon tax will be a "win-win" for the economy—by reducing distortions from the tax code as well as providing environmental benefits. On the contrary, it is theoretically possible and empirically likely that a revenue-neutral carbon tax will impose more deadweight loss on the economy, offsetting at least some of the potential environmental benefits. A carbon tax may still be a good policy, but its proponents should first understand the tax-interaction effect before making their case and choosing the tax level.

Effects of School Lunch Policies

This humorous vi​deo by some students in Kansas takes on the changes in the school lunch program brought on by the Healthy, Hunger-Free Kids Act of 2010.  

Although the kids mainly take issue with the calorie restrictions in the Act, one of the more subtle points in the video is that kids have lots of options.  If they don't like what's being offered at school, they can go off campus or just wait till they get home.  The ability of students to substitute tends to limit the effectiveness of school lunch interventions.  For example, this study found that: 

students who eat school lunches tend to consume fewer vegetables away from school, indicating that there might be some substitution effect present

​and

A policy of no store or snack bar leads to increased consumption of fruit in school. At the same time, there is some indication this policy is associated with less fruit and vegetable intake at home

A parody on the national school lunch policy mandated by The Healthy, Hunger-Free Kids Act of 2010 which humorously shows the results of the limitations in carbohydrates and proteins. No copyright infringement of original song "We Are Young" by Fun. was intended.

School Lunch Mess

With school back in session, there is a lot of consternation being expressed over the new school lunch rules being implemented by the USDA  as a result of the new policy promoted by Michele Obama.  Ironically one of the biggest complaints of the "Healthy Hunger-Free Kids Act" is that kids are hungry because of calorie restrictions.  

Another complaint is that kids don't like (and won't eat) some of the foods served.  Even before the law was fully implemented, one school official noted​:

Nothing is achieved when money is spent on food that children won’t even be able to consume and nothing is more disheartening . . . than to see perfectly good and perfectly untouched food thrown into the trash.

​And, yet another complaint is the rising cost of school lunch, which encourages kids and parents to future substitute away from the government-subsidized meals.  

As I put it in my forthcoming book, The Food Police​, the school lunch program is trying to do to much:

So, we have a mess - a convoluted mix of policies that try to get enough calories in the bellies of poor kids so they’re not starving at night while simultaneously trying to get the richer kids who can have anything they want at home to eat a few more carrots at school.

    ​and (footnote omitted):

My point isn’t that parents and local school boards shouldn’t think about how to improve their children’s health. My question is who is in the best position to make this determination? It’s easy for someone in Washington to enact mandates without any knowledge of the location-specific costs and trade-offs. As a USDA report put it, “Policymakers face hard choices because the children served by NSLP have diverse nutritional needs, making a single policy for all difficult to craft.”

​

Childhood Obesity and Fast Food Restaurants

​Yesterday Rudy Nayga, the Tyson Chair in Food Policy Economics from the University of Arkansas, visited my department and gave a seminar on the relationship between childhood obesity and the location fast food restaurants in relation to schools.

​He gave a careful account of the difficulty in attributing causation (and not just correlation) between the distance of fast food restaurants to schools and children’s weights, and described the ways they tried to deal with the challenge. In short, he finds that for every extra fast food restaurant within a mile of an elementary school, the percentage of students at the school who are obese goes up by about 1 percentage point.

As you might imagine, the result provoked a lot of discussion. Some of it naturally revolved around the efficacy and effectiveness of new zoning laws. However, the most interesting part of the discussion for me was Rudy’s discussion on the sizes of cafeterias relative to the increasing study body, which results in many school children have to eat lunch as early as 10am! In many schools (including my own kids’ school), children have to be run through the cafeteria so quickly they hardly have time to eat. Couple that with the new federal guidelines limiting the number of calories that can be served, and it is no wonder many kids are starving by the time school gets out and beg to go to McDonalds!

In addition all the above, I'd also add that because of increased curricula requirements, PE has been cut to the bone in most schools.

Alas, it seems most of the discussions I hear about improving childhood health in schools revolve around "sexier" headline-grabbing issues like serving more fruits and veggies, serving more local foods, zoning rules, banning sodas, teaching gardening, and so on. It may just be that the less "sexy" (and potentially less costly) issues like encouraging exercise, increasing cafeteria time or size, or giving a small afternoon snack, may be more promising.

And, at the end of the day, we have to keep in mind that it is not just childhood obesity that is a concern.  We also have to worry about childhood hunger.