It’s a Saturday morning in 2007. While most children are watching cartoons, others are doing step aerobics in front of their TV. Why? Because a video game told them they are obese.

The launch of Nintendo’s Wii Fit revolutionized the public’s perception of video games. For the first time, games could be used to improve a player’s health and wellbeing instead of impairing it. In Wii Fit, players are assigned a “Wii Fit Age” based on their actual age, Body Mass Index (BMI), and balance: the younger you are, the more fit you are.

When players weigh themselves in Wii Fit, their avatar changes in size accordingly. Players who are overweight or obese will see their avatar grow a large belly and hang their head in shame, accompanied by pitiful sound effects. Lead developer of Wii Fit Shigeru Miyamoto envisioned “it would be fun for people to measure their weight in the living room with the whole family” and “poke fun at Dad who’s put on a little weight.”

The problem with the definition of fitness according to Wii Fit is that BMI alone cannot predict a person’s health risk. Additionally, Wii Fit uses the adult BMI scale that classifies healthy children as overweight when they are not. This self-weighing has been associated with decreases in body satisfaction and self-esteem in adolescents. By defining a player’s level of fitness in terms of their weight, the non-scale benefits of exercise— like increased energy and better sleep —are ignored.

Nintendo redefined fitness in exergames with their 2019 release, Ring Fit Adventure. In Ring Fit Adventure, success is not measured by the player’s weight. Instead, players are encouraged to set wellness goals with everyday life in mind, like taking the stairs more at work and going on longer walks with the dog.

Exergames are a fun way to get active, and there is no doubting that Wii Fit was a pioneer in bringing this genre to the mainstream. Yet when fitness is defined by weight alone, exergames can foster negative attitudes towards exercise and one’s self. The new generation of exergames holds promise that video games can change our wellbeing for the better, instead of just changing the number on the scale.