Expanding definitions of obesity may harm children

A new and expanded definition of childhood overweight and obesity expected later this year is causing concerns that many healthy children may be unnecessarily labelled as having a disease.

A powerful “expert committee” in the United States has tentatively decided to reclassify children who are currently called “at risk of overweight” and refer to them in the future as “overweight.” Those familiar with these definitions say that such a change could lead to a dramatic expansion of prevalence estimates, with 25% of American toddlers and almost 40% of children aged 6 to 11 years portrayed as having a medical condition called “overweight and obese.”

The influential expert committee was convened by the American Medical Association and federal government agencies and includes representatives from leading professional organisations. It looks set to make changes to the current terminology, despite serious concerns expressed in a memo to the expert committee from two senior public health researchers.

The strongly worded memo argues that many children may be classed as diseased when they are not in fact even at risk of future illness; that the body mass index (BMI) cut-off points that determine “overweight and obese” are arbitrary, and although synchronising definitions for adults and children seems superficially appealing, BMI may not be a good predictor of fatness or future health problems in children; and that labelling children as overweight and obese can lead to stigmatisation, eating problems, and avoidance of physical activity.

Figure 1.

In future, 25% of US toddlers are likely to be classified as having a medical condition described as “overweight or obese”

Credit: RIC FIELD/AP

A University of Sydney researcher and nutrition educator, Jenny O'Dea, whose work on the dangers of medicalising childhood obesity was cited in the memo, said that the proposed change will cause a “misleading, inaccurate, and unnecessary labelling of children.”

One of the driving forces behind the expert committee is William Dietz, a senior member of the drug company funded International Obesity Task Force. For some years one of the task force's goals has been to frame the problem as a “serious medical condition.” (See accompanying story p 1412.)

Dr Dietz, a highly regarded official with the Centers for Disease Control and Prevention, and others involved with the expert committee declined to comment on concerns about the proposed changes to the definition of childhood overweight and obesity, scheduled for release by September this year.

A representative of the federal health authorities said the current expert committee effort had been initiated by Dr Dietz and that “no final decisions have been made as to finalising the recommendations.”