Dr. Taveras and Dr. Cardel are concerned that the Kurbo app should not be directly aimed at children, and that children should not be advised to do this on their own without parental involvement. (The app is free; users can pay to be paired with virtual coaches, a service that is marketed heavily to parents.) They have specific concerns about whether the classifications for certain foods are based more on quantity and calories, rather than on quality, and they really dislike the pictures with kids’ “success stories” on the app, since those are all about weight loss and appearance, instead of about balanced, proportional growth and healthy activity.

“They should have known better,” Dr. Taveras said, pointing out that the fine print — as always — says these are not typical results, and therefore not appropriate for showing to impressionable children.

Another concern that has been raised about the new app is that putting too much emphasis on weight loss may lead to low self-esteem, depression and eating disorders. Dr. Cardel cited a systematic review published this May that found that face-to-face treatment programs for pediatric obesity decreased the risk of eating disorders — but those were professionally supervised interventions, not apps.

“I certainly don’t want to discount that eating disorders have a high mortality risk, and we always take the approach of ‘first, do no harm,’” Dr. Cardel said. But we also do need to take into account the health issues of obesity, she said, which affects almost one of every five children from 2 to 19 years old, and one in four children in lower socioeconomic groups. It is linked to cardiometabolic disease and certain types of cancer, and also affects a child’s emotional health.

Anyone who works with children and families knows this is a sensitive topic, complex to bring up and difficult to discuss. I’ve written before on the topic of weight-shaming and fat stigma, both in the pediatric office and in the family in general. (On this Thanksgiving column two years ago, the comments reflect readers’ painful memories of family brutality around the table as well as fat-shaming, parent-blaming thoughts.)

“I never use the word dieting, and I never use the word weight loss, because of the negative connotations,” Dr. Taveras said. “But I can recommend that a family switch from sugar-sweetened beverages to water, or replace processed, calorically dense foods with fruits and vegetables — is that a diet? It’s a nutrition plan.”

In the primary care setting, Dr. Taveras said, “I always ask permission, even for talking about B.M.I. and weight, allowing a parent and family to say, you know what, this is something really sensitive to us.”