Nintendo has admitted that Wii Fit body fat readings may not be accurate for younger players, nor for sporty people carrying lots of muscle mass.
The platform holder was responding to criticism from British newspaper the Daily Mail, which heard from one troubled father that his young and supposedly athletic daughter had been devastated to find out she was "fat" according to the game.
He said it was the last thing she needed to hear in the face of today's stick-sized obsessiveness.
His comments prompted Tam Fry of the National Obesity Forum to declare that the "far from perfect" BMI system should "simply should not be used" with children, and that Wii Fit should at least carry a warning for parents preparing them for misleading results.
"Nintendo would like to apologise to any customers offended by the in-game terminology used to classify a player's current BMI status, as part of the BMI measurement system integrated into Wii Fit," responded Nintendo in an official statement.
"As stated in the Wii Fit manual, BMI is essentially a measure of body fat, based on an adult height and weight. Wii Fit is still capable of measuring the BMI for people aged between 2 and 20 but the resulting figures may not be entirely accurate for younger age groups due to varying levels of development.
"People with more muscle mass than normal will also have a higher BMI rating due to the heavy weight of muscle tissue, so the resulting figures should be used for reference purposes only," added the statement.
Nintendo went on to say that it was the "best generic" scale for measuring progress in its game, as the BMI system is "widely used within the medical and fitness professions".
You can also hide your on-screen weight and class yourself as a Guest so you do not have to take part in the BMI measuring process.
Wii Fit was released in Europe at the end of April and sells in shops for GBP 70 with the fancy Wii Balance Board.
We dressed Ellie up in Lycra to put it through its paces. Pop over to her Wii Fit review to find out what she thought.