Red light, green light: Food choice made easier
January 7th, 2014
08:01 AM ET

Red light, green light: Food choice made easier

What if eating healthy was as easy as playing your favorite childhood game?

In March 2010, Massachusetts General Hospital's cafeteria got an overhaul. Healthy items were labeled with a "green light," less healthy items were labeled with a "yellow light," and unhealthy items were labeled with a "red light." Healthier items were also placed in prime locations throughout the cafeteria, while unhealthy items were pushed below eye level.

The "Green Light, Red Light, Eat Right" method is a favorite among experts fighting childhood obesity. But doctors at Massachusetts General wanted to know if the colors could really inspire healthier eating habits among adults long-term.

The results of their study were published Tuesday in the American Journal of Preventive Medicine.

The study

A cash register system tracked all purchases from the hospital's large cafeteria between December 2009 and February 2012. The first three months of data were used as a baseline for comparison purposes. In March 2010, all food and beverages were labeled with a visible green, yellow or red sticker. Those with a green sticker were put at eye level and in easier-to-reach places.

Signs, menu boards and other promotions were used to explain the changes around the hospital.

The cafeteria had an average of 6,511 transactions daily. Approximately 2,200 of those were from hospital employees who used the cafeteria regularly. Twelve months into the study, researchers analyzed the number of purchases from each color group, and compared them to the baseline totals. They did the same at the end of the 24-month period.

The results

The number of red items purchased during the study period decreased from 24% at the baseline to 21% at both the 12 and 24-month follow-ups. The biggest decrease was seen in red-labeled beverages (such as regular soda) - from 27% at baseline to 18% at 24 months.

Sales of green items increased from 41% to 46%.

In other words, cafeteria-goers bought more water and purchased healthier food items during the study period than they did before the traffic light system went into place.

Employees showed the biggest improvement; their purchases of red items decreased by about 20%.


"These results suggest that simple food environment interventions can play a major role in public health policies to reduce obesity," the study authors write.

Lead study author Dr. Anne Thorndike wasn't sure that the changes seen early in the study would last over the two-year period. The consistent results at 24 months suggest people won't grow tired of or immune to helpful food labels, she says.

Thorndike does not believe the color coding system can replace more detailed nutrition information, but says the labels "convey some basic nutrition information in a format that can be quickly interpreted and understood by individuals from diverse backgrounds."

It's unclear if the traffic light system produced the change in consumers' behavior or if it was the rearrangement of items in the cafeteria.

Use it at home

"Families could utilize this concept by categorizing foods in the household as 'green' or red,'" Thorndike says. "For example, you could have a 'green' snack drawer or shelf on the refrigerator that the kids could freely choose from, and you could designate a 'red' drawer in which the kids would need to ask permission before taking a snack."

Parents can also rearrange their cupboards to put healthier snacks front and center. Sorry, cookies - it's the dark corner up top for you.

soundoff (19 Responses)
  1. Say waa?

    My wife gave me a big red light last night, I'll tell you that.

    January 7, 2014 at 14:30 | Report abuse | Reply
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  2. Kevin

    Or you could just not buy the unhealthy foods like cookies and sweets and not have them in the house as a choice at all. Instead of trying to hide or deny your kids something unhealthy, you could lead by example and teach them how to make healthy choices when shopping.

    January 7, 2014 at 17:35 | Report abuse | Reply
  3. morganzax

    What happened to the cafeteria's profit margin when people started buying more perishable vegetables and fewer shelf-stable junk items full of subsidized corn sugar?

    January 7, 2014 at 23:41 | Report abuse | Reply
    • VladT

      The makers of HFCS muscled in on the turf, and they warned the Hospital...

      "Be a shame if anything happened to the cafeteria." The goons then started throwing trays everywhere.

      January 11, 2014 at 04:42 | Report abuse |
  4. Kelli @ healthierbytheweek

    As a physician I think this idea is very interesting. The vast majority of adults and kids do not know how to read nutritional labels. Marketing of food products is very good at tricking people into thinking things are "healthy."

    January 8, 2014 at 15:18 | Report abuse | Reply
  5. Annonymous

    This is nothing new. My pediatrician tried this on me 25 years ago when I was an overweight child. At the time, it was called "The Red Light, Green Light Diet." A red, yellow, and green sheet with various food suggestions were taped to my fridge. Let's just say, 25 years later, I'm morbidly obese and have struggled with my weight since childhood.

    January 10, 2014 at 15:29 | Report abuse | Reply
    • rupert

      Anonymous. Hang in there. Try your best.

      January 12, 2014 at 18:25 | Report abuse |
  6. Jennifer

    I like the idea of using traffic light colors to clearly label the food. In today's society where many people are busy with their careers (or some people are just uneducated about the dangers in some food groups), some people don't have the time to cook or think twice about all the ingredients that went into making the food. As a result, people unknowingly consume food that appear "normal" or "standard" but after years of consuming those foods (fast food, sugar, cakes, surgery drinks), many people are diagnosed from tumors to cancers to diabetes to skin infections, etc.

    I hope the "red light, yellow light, green light" labeling extends outside the study at Massachusetts General Hospital.

    January 11, 2014 at 15:46 | Report abuse | Reply
    • Ed

      Gosh, them thar "surgery drinks" must be hell on a body!

      January 11, 2014 at 18:24 | Report abuse |
  7. rupert

    Pizza, fries, fat steaks, greasy tacos.

    January 12, 2014 at 18:21 | Report abuse | Reply
  8. Jen

    It depends on what the traffic light colours are based on, ie are they just based on calorie count, salt, sugar and fat content, or do they also consider whether the product is real food or not? Dieticians are notorious for ignoring food additives in the advice they give, with a history of recommending artificial junk like margarine, additive-filled wholegrain breads and tuna in BPA-lined cans.

    Personally, I would ignore the traffic lights and continue to read the ingredients list as I currently do, putting back anything which isn't real food.

    January 14, 2014 at 02:50 | Report abuse | Reply
    • Nobody you know

      "Dieticians (sic) are notorious"? Since when? Can you cite an example?

      January 14, 2014 at 08:50 | Report abuse |
  9. Cycled

    I bought an app over the holidays that actually uses this same traffic light coding – GO meal and fitness – so I guess they're ahead of the curve.


    I have a health issue with specific dietary guidelines and I've been using the app for 3 weeks to keep myself on track. My friend is using it to keep herself accountable for weight loss. We're both photo capturing our food (we both hate the usual calorie count apps).

    It's working really well for us.

    Whatever your personal traffic lights are it's a good way to reinforce positive behavior.

    January 15, 2014 at 09:19 | Report abuse | Reply
  10. Stacey

    I work at a hospital in Pennsylvania and they have also gone to this type of program at the beginning of 2013. The program is called "Eating Well Matters". They did away with some of the unhealthy foods they served and brought in new options. Some of the new foods didn't go over well and they ended up bringing back some of the unhealthy favorites. They have also provided us with the nutritional information for the food they serve. At first it took some getting use to and not everyone was pleased with the change. But I think it's helped us all make better educated choices when it comes to our food.

    March 14, 2014 at 11:27 | Report abuse | Reply
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