WW, the company formerly known as Weight Watchers, announced this week it's offering a new free app for teens and kids as young as 8.

Called Kurbo Health, the app is based on research from Stanford University's Pediatric Weight Control Program, and uses a "traffic light" system to categorize foods' health. The company says it's intended to help children manage weight by helping them develop healthy habits with an easy-to-use tool.

But the app and accompanying marketing campaign have generated outrage online from some health experts, parents, and people who say early experiences with diets caused them to struggle with body image and eating disorders.

Before and after "success stories" on the Kurbo website, showing kids who have lost weight or reduced their body mass indexes, have added to the controversy.

Read more: Weight Watchers has changed its name to 'WW' to focus on overall wellness — here's what's actually changing about the program

WW says Kurbo is intended to foster healthy habits at a young age

Launched in 2014, Kurbo was designed to make information on body mass index, healthy eating, and weight loss accessible to kids and their parents.

It was acquired by WW in 2018 for $3 million. Prior to the recent launch, WW made several changes to the program, including the addition of tracking metrics and goals like "lose weight," "make parents happy," and "feel better," TechCrunch reported.

Users are asked to track their food intake using a "traffic light" system.

Foods that can be eaten any time, like vegetables, are green; foods that are healthy in moderation, like proteins and pasta, are yellow; and food that should be limited, like candy and soda, are red. Beans and avocado are also categorized as "red light" foods, although they are highly nutritious.

Kurbo rewards users for consistency with "streaks" (similar to Snapchat) for each consecutive day of tracking.

The app is aimed at addressing "extraordinarily high" rates of obesity in the US, and the associated "medical and psychosocial consequences," Gary Foster, chief science officer at WW, told INSIDER.

"There is good data that children are not likely to grow out of it and overweight people who have been since childhood have more medical problems," said Foster, who has a PhD in psychology and has done extensive research on obesity treatment.

He said the app is intended not to focus on weight loss, but to be a resource on the foundations of healthy eating.

"Some of the most unhelpful things said to a child or teen about weight come from inside the home," he said. "This is teaching parents to talk about it in a way that's positive and not punitive."

Although the app itself is free to use, the coaching feature is a paid subscription service that costs $49 to $69 a month.

Some health experts say the app is a diet in disguise

The Kurbo launch has generated an outcry from nutritionists, parents, and survivors of eating disorders, who say the app is similar to other forms of dieting that can increase risks of eating disorders and obesity in young people.

Many people on social media have pointed out that elements of the app itself seem to contradict WW's insistence that it's more about healthy habits than weight loss. One Twitter user posted a screenshot of the app's instructions to "count every food you put in your body" and "round up" even small bites of "red light" foods.

Critics have also objected to marketing that includes before and after pictures of users as young as 8 cited as "success stories" on the Kurbo website.

"Just because you say something's not a diet, doesn't mean it's not a diet. It's a code because it's not okay to say 'diets for kids,'" said Rebecca Scritchfield, a registered dietitian nutritionist and author of "Body Kindness," a book about developing healthy habits and positive body images without dieting.

She objected to the traffic light system as stigmatizing certain foods, even though it doesn't outright prohibit them.

"It operates on a high amount of shame. A traffic light system is going to teach you to associate negative emotions with certain foods, that bad foods equal a bad person," Scritchfield said.

Certified nutritionist Anna Sweeney, who has been outspoken about her opposition to the app, said it's "irresponsible" that the app implicitly encourages weight loss goals through its marketing.

"Suggestion that there should ever be a before and after weight change photograph of a child is horrifying. Weight gain during childhood and adolescence is intentional. If it does not happen, there is a medical problem at hand, " she wrote on Twitter.

This isn't the first time WW has come under fire for developing programming for kids

Last February, critics also took issue with WW's announcement that it would be opening up its program to teens for free. The Balance Eating Disorder Treatment Center started a hashtag, #WakeUpWeightWatchers, which was trending again August 14 and 15, for people to express their concerns. Critics argued the move sends kids the message that their worth is weight-based, and sets them up for a lifelong unhealthy relationship with food, if not a full-blown eating disorder.

WW didn't change its plans as a result of the backlash, and as evidenced by the Kurbo launch, is moving even further into the teen space.

The new app, Foster said, is designed to counteract advice about eating and weight that kids might be getting from unreliable sources like social media. He cited research from the Center for Disease Control and Prevention saying that 45% of teen girls have tried dieting, including detox teas and aggressive calorie restriction.

"What we think we're doing is giving context to what's a reasonable way of doing this, and maybe inoculate people against some of the things they're hearing," Foster said. "Put against a lot of unhealthy habits out there, we're really proud of our ability to bring a science-based approach to healthy eating."

A better way to promote children's health, Scritchfield said, is to promote a cultural shift from "problem" foods and calorie tracking to offering a variety of options as part of a balanced plate with every meal or snack.

"Why are we still a culture that centered weight loss and bases people's worth on their size? Is this the kind of world we want to create for our kids?" Scritchfield said. "You can encourage truly healthy behaviors without centering weight loss and that's going to include all kids, no matter what they weigh."

By: Gabbi Landsverk