Global Strategy on Diet, Physical Activity and Health

Frequently asked questions: Childhood obesity

Reviewed August 2014

What is obesity?

Obesity is defined as abnormal or excessive fat accumulation that may impair health. In infants and children under 5 years of age obesity is assessed according to the WHO "Child growth standards" (weight-for-length, weight-for-height) and the WHO Reference for 5-19 years (body mass index-for-age).

How does this differ from the way obesity is measured in adults?

In adults overweight is defined as the individual’s body mass index (BMI). This is a simple index of weight-for-height, defined as a person's weight in kilograms divided by the square of his or her height in metres (kg/m2). In adults BMI greater than or equal to 25 is overweight; and BMI greater than or equal to 30 is obesity.

What are the health consequences of obesity in childhood?

Obese infants and children are likely to continue being obese during adulthood and are more likely to develop a variety of health problems as adults. These include:

  • cardiovascular disease
  • insulin resistance (often an early sign of impending diabetes)
  • musculoskeletal disorders (especially osteoarthritis - a highly disabling degenerative disease of the joints)
  • some cancers (endometrial, breast and colon)
  • disability.

How can childhood obesity be prevented?

Supportive policies, environments, schools and communities are fundamental in shaping parents’ and children’s choices, making the healthier choice of foods and regular physical activity the easiest choice (accessible, available and affordable), thereby preventing obesity.

For infants and young children, WHO recommends:
  • early initiation of breastfeeding within one hour of birth;
  • exclusive breastfeeding for the first 6 months of life; and
  • the introduction of nutritionally-adequate and safe complementary (solid) foods at 6 months together with continued breastfeeding up to two years of age or beyond.
School-aged children and adolescents should:
  • limit energy intake from total fats and sugars;
  • increase consumption of fruit and vegetables, as well as legumes, whole grains and nuts;
  • engage in regular physical activity (60 minutes a day).
The food industry can play a significant role in reducing childhood obesity by:
  • reducing the fat, sugar and salt content of complementary foods and other processed foods;
  • ensuring that healthy and nutritious choices are available and affordable to all consumers;
  • practicing responsible marketing especially those aimed at children and teenagers.

Why has WHO formed a high-level commission on childhood obesity?

At present, there is lack of consensus worldwide on which approaches and which combinations of these interventions are likely to be most effective to prevent childhood obesity in different contexts and societies. The high-level Commission on Ending Childhood Obesity has been tasked with garnering advice from experts around the world and making recommendations to the WHO Director-General on how to tackle the current crisis.

No single discipline can provide the groundwork for a strategic approach to tackling childhood obesity. Social scientists, public health specialists, clinical scientists and economists will join together to synthesize the best available evidence into a coherent plan. Actors responsible for maternal health and nutrition; child health, education and health literacy; physical activity; and public policy will also engage in the task.

How will the experts be involved?

The Commission will be supported by two working groups. One group will examine all available evidence on prevention of childhood obesity and how to reverse it in affected children; and determine the best combination of policies to put in place to achieve these goals. The second group will determine how to monitor achievements in tackling childhood obesity worldwide and track results. Their work will form the basis for a report from the Commission.

When will the results of the Commission’s work become available?

The Commission will deliver its report to the WHO Director-General so that she can convey its recommendations to the World Health Assembly.