Why your child could be obese and you don’t even know it

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Obesity is an important problem in the United States and around the world.  A new study from researchers at New York University suggests that part of the problem is that parent’s underestimate what normal body weight is in children.

This study suggests parents do not realize their kids are overweight, how did they come to that conclusion?

In 1988-1994 researchers asked parents of ~3,000 children whether or not their children were overweight, normal, or underweight and compared the results versus the medical determination of BMI or Body Mass Index at that time.  Using the same format, researchers repeated this study from 2007-2012 in 3,000 children and compared the results.  Roughly 95% of parents of overweight boys and 90% of overweight girls thought that their children were normal weight.  And even though there are more overweight children now than in the early 1990s, parents were still no more likely to identify their children as being overweight than in the past.  While this study was in children 2 to 5 years old, this is consistent with previous studies in children with a wide age range.  In a meta-analysis of 69 trials, 51% of parents with overweight or obese children misclassified their children as having normal weight.

Why can’t parents accurately make this determination?

BMI calculation is not very intuitive.  There is one standard range for normal blood pressure, or for normal amounts of sodium in your blood but there is a host of acceptable weights based on changes in height so the value needs to be calculated.  So what do parents do?  They use comparisons to themselves and other children to determine what is normal.  If the parents look at other children and their child is similarly sized, or if the children body shape is like their own, that becomes normal even if the entire group is overweight.

How is BMI calculated? What is normal?

If you search online for BMI Calculator, there are several sites that will do the math for you.  Once you have the number here is the breakdown: underweight is <18.5, normal is 18.5–24.9, overweight is 25–29.9, and obesity is 30 or more.  The take home message is that a healthy normal weight isn’t something that you can just eyeball and if you don’t now there is a problem; you cannot make the changes you need to prevent the negative health effects for you and your family.  That isn’t to say that weight loss is easy but the sooner you can establish health eating and exercise habits in your children the more likely they are to become lifelong practices.

Dr. Michael White, Department of Pharmacy Practice, UConn School of Pharmacy