I've long been concerned about implementing public health policy without really studying it. Sometimes, it's because I worry the policy won't work. Sometimes, it's because I think the policy will cost a lot of money, and it won't be worth the results. And - sometimes - it's because I worry that the policy might backfire. A good example of this last concern was illustrated in a recent study in the American Journal of Public Health. "The Unintended Consequences of Changes in Beverage Options and the Removal of Bottled Water on a University Campus":
Objectives. We investigated how the removal of bottled water along with a minimum healthy beverage requirement affected the purchasing behavior, healthiness of beverage choices, and consumption of calories and added sugars of university campus consumers.
Methods. With shipment data as a proxy, we estimated bottled beverage consumption over 3 consecutive semesters: baseline (spring 2012), when a 30% healthy beverage ratio was enacted (fall 2012), and when bottled water was removed (spring 2013) at the University of Vermont. We assessed changes in number and type of beverages and per capita calories, total sugars, and added sugars shipped.
As the article states, American use about 50 billion plastic bottles each year, almost 80% of which end up in landfills. There are environmental consequences to this fact. Plastic bottles, especially those intended for single-use, don't degrade easily, consume a lot of resources, and take up a lot of waste disposal resources.
In response to this, many colleges and universities have banned the sale of bottled water. On its face value, this seems like a reasonable response if your goal is to reduce the amount of plastic waste your campus is producing. But there's a catch. One of the reasons that bottled water was becoming more popular was because people were turning to water as a beverage choice instead of drinks with calories, like soda, juice, or milk. That was also a good thing, as beverages with sugar are thought to be one of the causes of the obesity epidemic.
This study was an attempt to see how a ban on bottled water might affect people's choice of beverages in general. Researchers looked at shipments of beverages to the University of Vermont before, during, and after the ban went into effect. The outcomes of interest were number and types of beverages consumed, the number of calories per person consumed, and total and added sugars shipped.
After the ban, the number of bottled beverages shopped overall went up. Concerningly, though, so did the number of calories (3249 to 3958 kcal), total sugars (714 to 864 g), and added sugars (528 to 638 g). The overall nutritional value of beverages shipped went down significantly. Here's the chart you need to see:
Yes, the percent of sugar-free beverages increased. But so did the percent of sugar-sweetened beverages. It appears that people want portable beverages that they can drink. If they can get bottled water, they will drink that. But if they can't, they will choose other beverages rather than start to bring their own water. That may be good for the environment, but it's not clear that's good for health.
So was this policy bad? I don't know the answer. It's possible that the environmental gains of banning bottled water outweigh the harms of drinking more sugar-sweetened beverages. But I'm not sure. What I do know is that many, if not most of the discussions I see about colleges taking action like this focus only on the potential harms of plastic, though. I see too few thinking about the unintended consequences for health. A balanced discussion would consider both. Without research, that discussion can't take place. We need both when we consider and implement policy.