No fewer than 41 million children under five worldwide are obese or overweight.
This was made known by the World Health Organisation (WHO) on Wednesday.
According to the UN health agency experts at the launch of new guidelines to tackle a global epidemic, WHO said it was faced with evidence indicating that the problem affected rich and poor countries alike.
WHO therefore released details on how trained professionals could identify youngsters in need of help better.
The obesity guidelines which just published included counselling and dieting, an assessment of eating habits along with the more usual weight and height measurements.
WHO said the prevalence of obesity in children reflected changing patterns towards unhealthy diets and physical inactivity.
“Urbanisation, increased incomes, availability of fast foods, educational demands, television viewing and gaming have led to a rise in the consumption of foods high in fats, sugar and salt and lower levels of physical activity.
“While there have been major public health interventions to promote improved diet and patterns of physical activity in adults, the contribution of antenatal and young-child interventions to reducing the risk of obesity in later life have not been significantly reviewed,” WHO said.