A new Fitbit wristband called Fitbit Ace has been launched for children over eight. It will feature “reminders” for them to get active, undertake family step-challenges and also monitor sleep patterns. Thankfully, the calorie-counting device found on normal Fitbits has been disabled, but is that enough?

Bearing in mind the UK’s child obesity problem – according to figures from NHS Direct, a third of children between two and 15 are overweight or obese – some people may feel that the Fitbit Ace could only be a boon. However, that’s debatable. Children are already bombarded with harmful messages about body image. Overweight kids are teased. Normal-sized girls feel that they should be on strict diets. Even young boys are succumbing to anorexia. Do children need what amounts to a “fat-shaming toy”?

While many teenagers have owned Fitbits, the difference was that they were officially perceived as adult products, set apart from the child’s world. Now there’s this designated child-fitness “toy” pumping out information that’s arguably too complex for a young mind to properly process.

While the Fitbit Ace is monitoring physical progress, who is monitoring the child’s reactions and emotions? After all, motivating children to get fit is just one important aspect; another would be stopping them from going too far with what may feel like a new playground craze.

What may seem like a harmless motivational gimmick could lead an immature mind into disturbing, obsessive behaviour. Orthorexia (the type of anorexia that masks itself as a health and fitness obsession) is a very real issue that should not be encouraged in anybody, never mind children. The good news is that there are already devices widely available to encourage most children to be healthier and fitter – they’re called parents.

• Barbara Ellen is an Observer columnist