The global childhood obesity epidemic has exploded. Over the past four decades, the world has witnessed a tenfold increase in obesity in children and adolescents between five and 19 years old.
More than 124 million children across the world are currently considered to be obese. In children under the age of five, obesity used to be nearly unheard of. Now, more than 38 million young children live with this condition.
Researchers now estimate that there are more obese children than underweight children worldwide. Children and adolescents who are obese are more likely to become obese adults, setting them up for a lifelong trajectory of poor health.
With this growth in childhood obesity comes an increase in associated poor mental and physical health outcomes. Conditions that were once rare in children are now becoming increasingly common. These debilitating and costly diseases include hypertension, Type 2 diabetes and others.
I am a public health researcher who studies and teaches about the factors underlying the obesity epidemic. My research seeks to understand what is driving these trends. Why are more and more people, including children, becoming obese?
Parsing the numbers
Childhood obesity was once predominantly an issue within developed nations. But it has become an emerging health concern, even in the poorest countries and regions.
The standard measure used to determine obesity in children and adolescents has long been the body mass index, or BMI. This is a measure of an individual’s height as compared with their weight. Children whose BMI is a set threshold above the mean, or average, are considered obese. The role of BMI in defining obesity in children and adults may be changing, however.
Although BMI remains a low-cost and practical method for assessing obesity across populations – such as estimating the percentage of children in a particular nation who are obese – growing evidence has shed light on its limitations for use at the individual and clinical level. Leading medical organisations and researchers are encouraging physicians to consider the use of alternative measures, which may change the way children are screened for health risks related to their weight at the doctor’s office.
Critical role of parents and caregivers
In essence, childhood obesity is the result of kids eating and drinking more calories than they are burning off through play, movement and growth. Because of this, researchers have largely focused on understanding the individual eating and physical activity habits of these kids.
In the case of childhood obesity, researchers like me also know that parental figures play critical roles in both mirroring and creating opportunities for physical activity and healthy eating.
However, attempts to address childhood obesity have often focused excessively on individual behaviours of parents and children, and too little on the environment where children and their families live. Research and statistics make it clear that this approach has failed and that new strategies are needed to understand and address why more children are becoming obese.