by Marion Nestle
Jan 27 2012

Guess what: Traffic light labels work

A study published online in the American Journal of Public Health fiddled around with red (avoid) and green (eat me) labels on items in a hospital cafeteria.

The investigators measured sales before the start of the intervention.  About a quarter of items sold were in the red category and 42% were green—these hospital workers were already making healthy choices.

The intervention took place in two 3-month phases.  The first phase just involved traffic light labels.  In the second phase, the investigators moved the items around to make the green-labeled products more visible and accessible.

The results: labels alone led to decreases in sales of red-labeled items and increases in sales of those with green labels.

For example, sales of red-labeled drinks decreased by 16.5%.  When the drinks were made less accessible, sales declined by an additional 11.4% (sales of bottled water increased).

No wonder the food industry in Great Britain fought so hard against traffic light front-of-package labeling.  No wonder the Grocery Manufacturers Association and Food Marketing Institute much prefer their own guaranteed-not-to-work system.

And data like these surely explain why the FDA is taking so long to do anything with the Institute of Medicine’s proposed labeling system—not exactly traffic lights, but pretty close.

This study provides further evidence for the value of such schemes for helping people make healthier choices.

FDA: get busy!


  • James Howell
  • January 27, 2012
  • 12:32 pm

Yeah but who decides which food is “red” and which is “green?” A bunch of bureaucrats?

I don’t have access to the PDF but did they label meat and saturated fat as “bad?” Do they recommend, I wonder, high-carb whole grains? Based upon their places of work, I’m willing to bet they do.

  • Adrienne
  • January 27, 2012
  • 12:47 pm

A few years ago, there was a program for teaching kids about “Go, Slow and Whoa” foods, corresponding to Green/Yellow/Red. It’s a powerful representation.

One mobile phone food diary/coaching tool uses this approach: Noom (the coaching tool which combines food & physical activity) and Calorific (the food diary part). Rather than keeping track of each individual food you eat, you keep track of how many Green/Yellow/Red foods you eat.

  • justthefacts
  • January 27, 2012
  • 1:30 pm

@ James Howell

EXPERTS in science and public health decide which food is red or green, that’s who. Sadly, many of them are employed by bureaucracies that get bogged down by politics that is guided by ideology rather than science.

  • justthefacts
  • January 27, 2012
  • 1:51 pm

See Marion’s post for Aug 16, 2011

“The Fuss Over Saturated Fat”

Note especially the comments at the end of the column.

[...] recently read an article about a study done to help people make healthier eating choices. The experiment was simple: red [...]

[...] quoi : l’étiquetage par des feux tricolores, ça marche (Guess what: Traffic light labels work) est un article de Marion Nestle paru le 27 janvier sur son blog Food [...]

  • Cathy Richards
  • January 27, 2012
  • 5:57 pm

Yes, the system really did work in Britain. I visit often and was quite impressed by it. Also, in 2006 they did a great presentation at a food policy conference in Ottawa. Here is the link to the presentation:

[...] read the article Guess What Traffic Light Labels Work posted on and it got me thinking.  A green label means a healthy food and a red [...]

[...] Marion Nestle reports on a study testing the efficacy of a simple “traffic light” syst… A study published online in the American Journal of Public Health fiddled around with red (avoid) and green (eat me) labels on items in a hospital cafeteria. [...]

[...] traffic cop. Lead employees to healthier choices with traffic light labels that make it easy to find and select the healthiest (or healthier) [...]

  • Derek
  • February 19, 2013
  • 5:32 pm

I wonder what the payer mix looks like? I’m guessing that a large number of the customers tend to be employees of the hospital who also tend to be health minded. Does this extrapolate to other areas… such as school cafeteria’s a la cart lines? The army uses this system extensively and anecdotally speaking, it seemed to be a big joke and not have much of an effect on many of the soldiers’, that I served with, decisions.

I actually thought the system was backwards. The color red stimulates hunger and does a good job at drawing someones attention. This is exactly why red and yellow are the brand colors for many fast food companies. Going through the lines looking at the poorly prepared casseroles (green) I always found my eye drawn to the big red sign that said bacon cheeseburger. It was like it was taunting me. I knew it was bad but craved it nonetheless. I have looked around online and can’t find a meta-analysis of studies of this type labeling system (stop lighting, traffic lighting) and I was wondering if you could point me in the right direction.

[…] years ago, a food attention — underneath vigour to adopt a color-coded nourishment complement — affianced to put “facts adult front” by displaying icons […]

[…] they compete. Research shows that categorizing foods according to a ranking system (such as a  traffic light system – Green: eat more often vs. Red: avoid), leads to smarter food choices. Since I’m […]

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