Thoughts on the Berkeley Soda Tax

This is a repost from the National Physician's Alliance Blog:

Many political pundits are trying to decipher the lessons from the 2014 midterm elections. I will not try and do that here. But, some of the most interesting results have come from ballot measures. While many people voted for conservative officials, these same voters voted to legalize marijuana, prevent a personhood amendment, and raise the minimum wage.

One of the most interesting measures that passed was the soda tax in Berkeley. San Francisco voters also voted in favor of the tax, but did not reach the 2/3rds majority needed to pass. (The 2/3rds threshold has to do with California law on new taxes.) Others have tried institute a soda tax. The two most notable examples were New York City and Richmond, CA. Both resulted in the American Beverage Association (ABA), an industry trade group, spending millions of dollars to defeat the measures. The ABA spent a few more million in the recent ballot initiative in Berkeley. By law, companies have a fiduciary responsibility to maintain profits for their shareholders. Thus, my conclusion is that they had to spend this money. They feared profits would decline if these measures passed.

The evidence is fairly clear on the likely effects of a soda tax. Various economists have done simulations to show that a tax will likely decrease consumption and purchasing. The health economists have also simulated how many people will be prevented from getting diabetes and heart attacks. Of course, all simulations are based on assumptions. Since we do not have an actual soda tax yet, it is hard to predict exactly what will happen.

But, early indications from data in Mexico, after their soda tax was instituted recently, is that sales are decreasing. If other assumptions hold up (e.g. that people will not go eat candy instead), Mexico’s policy could have an impact on public health. The effects will be more difficult to measure in Berkeley. Berkeley is a small city with many surrounding urban areas without a soda tax. It also has a population that is often changing, due to the University population. However, it still offers us an interesting experiment to see the possible effects of a soda tax. Particularly interesting will be the effect on Berkeley youth.

A signifiant consequence of Berkeley passing a soda tax is a possible ripple effect. Other cities interested in experimenting with public health policy could think about passing a soda tax. California has often been an experimentation ground for innovative policies. The policies preventing smoking in public places started here, leading the way for cities worldwide to institute these bans.

While libertarians may protest against these policies, people still have the freedom to choose whatever they like to purchase. Taxes already exist on other foods in California, such as restaurant food and frozen meals. The soda tax just adds sugary beverages to the mix, albeit at a slightly higher rate.

Finally, many believe that the actual tax is not the real intervention here. The tax on sugary beverages just gets us all talking about the harms of drinking 10 (or many more) teaspoons of sugar at a time. The media is talking about it. Social media is talking about it. If the tax in Berkeley signals to people that drinking sugar is not the “cool” thing to do, than maybe a few more parents will think twice about buying their kids a sugary drink.

Childhood Obesity, Headlines, and Jelly Beans

Remember that game where you guess how many jelly beans are in a jar? Well, if I guess once, I'll probably be wrong. But if I'm allowed to guess 500 times, I might get it right once. But that doesn't mean I'm a good guesser of jelly beans numbers.

The same concept applies to research studies. The more times you test a question, the more likely you are to get a postive result. That doesn't mean that the answer to the question is "yes". It just means you guessed so many times that your were bound to get a correct answer.

The New York Times Missed this point in their article when they wrote the headline:

"Obesity Rate for Young Children Plummets 43% in a Decade"

Sounds like a huge drop. I wish it was. But the researchers tested many age groups to see if there was a decline over 10 years. They checked the age ranges 2-5, 6-11, 12-19, 20-39, 40-59, and >60. When you "guess" if there is a decrease in obesity in all of these age groups, you are likely to find one "yes".

The researchers admit this and even caution interpreting their results this way:

"When multiple statistical tests are undertaken, by chance some tests will be statistically significant (eg, 5% of the time using α of .05). " 

And they conclude:

"Overall, there have been no significant changes in obesity prevalence in youth or adults between 2003-2004 and 2011-2012. "

Yet some how the New York Times missed this, and focused their headline on a minor result. While we might have made small gains against childhood obesity, we haven't really begun to change the trajectory of the epidemic.

 

Can Subway be Healthy?

Today, Subway announced a new agreement with the Partnership for a Healthier America (PHA). PHA is a non-profit group that was started by First Lady Obama to reduce obesity in America.

When I saw Mrs. Obama speak last year at the PHA conference, she was really starting to emphasize that marketing is a big cause of overeating. You can provide all the "health choices" you want, but if you price the unhealthy ones lower, and have ads all over the television for them, they are going to sell more.

The new PHA agreement with Subway takes a step in the right direction. As part of the agreement, Subway will form a policy on advertising to children. (Hopefully PHA will have to approve this policy.) In addition, they will spend $41 million to advertise fruits and veggies to children. This type of advertising is badly needed to compete with the billions of dollars that advertise junk foods to kids.

So the real question is: will this get kids to eat healthier at Subway? In our study of what teenagers buy at Subway and McDonald's, we found they were eating a lot of processed food, few veggies, and a lot of calories.

My view is that the change in marketing is a positive step. But, there is still a problem with much of the food at Subway. We found that teens ate 2,149 mg of sodium in a Subway meal. That's more than 3 times what the National School Lunch Program recommends. Now, in truth, salt amounts are not very important for young kids. But the amount of salt tells us that the food at Subway is highly processed. For instance, the meat and bread have a lot of salt because they are highly processed. And we know that processed food leads to many of the problems of obesity. Notably, in the agreement they were only able to agree to 935mg of sodium in kids meals. That is more than our panel of experts and RAND recommended (700mg).

How else could we know if kids are eating healthier at Subway? I would want to know if they are eating more vegetables. I do not see any specifics in this agreement about Subway reporting how many servings of veggies they are selling to kids. PHA often does require these types of reports, but I do not see it in the press release. The best way to study this is doing what I did: collect receipts from kids and calculate what they are eating. But, it would be much easier if Subway would give vegetable sales out, so that researchers (like me) could analyze it.

What happens if they do get kids to eat more veggies, and somehow less meat and refined grains? What happens when the kids get to the cash register? For those of you who frequent Subway, you know there is a giant display of cookies. The sales clerk almost always asks, "Would you like a cookie and a drink with your sub?" Having cookies at the cash register is a risk factor for disease. So the easiest thing Subway could have done to improve health is to move the cookies to a place kids are less likely to ask for them, and parents are less likely to buy them.

I congratulate Subway and PHA for the agreement, but would like to see some objective and public research/analysis. Without this analysis, the public will not know if this is another Subway marketing scheme or an improvement in what kids are eating.