No easy way to address weight issue with children

NEW YORK - Red, yellow, green. It's a system for conveying the healthiness of foods, and at the center of a debate about how to approach weight loss for children.

This month, the company formerly known as Weight Watchers provoked a backlash when it introduced a food-tracking app for children as young as 8. The app uses a well-known traffic-light system to classify foods, giving children a weekly limit of 42 "reds", which include steak, peanut butter and chips.

Obesity is a growing public health issue that nobody is sure how to fix, and around one in five children in the United States is considered obese, up from one in seven in 2000. Childhood obesity often leads to adult obesity, and to higher risk for conditions including heart disease, cancer and diabetes.