There are many factors that result in a red code for a food. The number one factor why many foods receive a red code is that they contain more than one gram of trans fat. Almost all of the foods at Taco Bell, for example, are coded red because they contain large amounts of trans fats. Many restaurants do not report the trans fat content of their foods-indicated in the table as not available (NA)—leading us to believe that they are still frying in trans fats. Consequently, they are coded red.
What about a pizza that doesn't contain any processed meat? Your basic cheese pizza gets a yellow code. Although it doesn't contain trans fats or processed meat, it also doesn't contain any vegetables or whole grains. It's kind of in the middle. That's what yellow foods are like. They aren't good enough to be coded green or bad enough to deserve being branded red. Some yellow foods include cheese pizza, sweet and sour chicken, a single taco or burrito, and frozen yogurt.
Green foods are the best. To earn the green badge of honor, a food has to have certain qualities that make it part of a healthy daily diet. Obviously foods made with whole grains, fruits, vegetables, and healthy oils will be coded green. Green-coded foods include vegetable pizza, many sandwiches, salads, eggs, and entrées made with vegetables, such as vegetable stir-fry. Green foods are low in saturated and trans fats, they don't contain excessive amounts of sodium or cholesterol, and they are relatively low in calories compared to yellow and red foods. They are actually good for you and could be eaten every day. By choosing green foods you can eat fast food and still eat healthy—the best of both worlds.