Why McDonald's new calorie labels won't work

The problem with nudges.

McDonald's. Photograph, Getty Images
McDonald's. Photograph, Getty Images

McDonald's is getting on board with a new Affordable Care Act, that aims to make people healthier by forcing them to confront just how unhealthy the food they are eating is. To this end, chain restaurants will have to put labels on all menus, showing customers how many calories each item includes.

Here is an extract from Mcdonald's press release, which quotes Judith C. Rodriguez, a Professor from the Brooks College of Health. She says:

The transparency and availability of nutrition information enables consumers to make choices and can help caregivers teach and model decision-making behavior to children. These are life skills that will benefit them not only at McDonald's but in every aspect of life.

But as Sarah Kliff in the Washington Post points out, health-based "nudges" like these have not had a very effective record. She points to a study from 2008, which looked at the reaction of New York City residents, which had already introduced calorie labels with those of Newark, which had not. Here's a table showing changed buying habits. There's a slight difference, but (read the notes below) not a significant one:

What's the hitch? Kliff suggests that the problem is that people simply don't know how many calories they are supposed to eat in a day. She indicates a survey by the International Food Information Council Foundation earlier in the year, which found only one in seven Americans knew the recommended daily allowance. Transparency of information doesn't always stop the message being opaque.

But I'd suggest the problem is deeper than that. Implanted "nudges" must take account of all the other nudges in our environment. Nudges like the food being delicious, and people being hungry. A number on the packet can't always counteract all of them.