Green means go, red means stop. Trophies and confetti reward good performance, while those who fall behind are nudged to improve. These brightly coloured engagement tactics have long since moved from smartphone games into everything from online shopping and sports betting to classrooms. So it is no surprise that many nutrition-tracking apps now use similar gamification features to keep users coming back.

But as nutrition apps continue to proliferate, some researchers are raising concerns that these gamified elements may do more harm than good for certain users.

Isabella Anderberg, a psychologist researching digital dieting behaviour at Flinders University in Adelaide, Australia, said calorie tracking can reinforce behaviours associated with body dysmorphia and disordered eating.