What does it mean to be overweight or obese?

The traditional definition of overweight and obese refers to the presence of excess fat tissue (excess body fat). A child that is overweight or obese has excess body fat, resulting from a calorie imbalance where more calories are consumed than used by metabolic processes, growth, daily functions, and activity.

Overweight and obese are medical “screening labels” used for ranges of weight that are above what is considered healthy for a given height and may increase the risks for certain diseases or health problems.

In children:

  • Obesity is defined as a basal metabolic index (BMI ) > 95th percentile
  • Overweight is defined as a BMI between the 85-94th percentile for children of the same age and sex. 
  • Normal weight is considered a BMI between the 5th and 84th percentile (see the next question for an explanation of BMI). 

However, these population based cutoffs do not take into consideration an individual’s genetic blueprint, which may put their healthy weight “outside” these definitions. This is why Healthy Kids believes it is more important to look at each child’s growth chart and assess for shifts (deviation) upward, reflecting excess weight gain for that individual, rather than rely solely on population data cut offs. 

This means that for a child who has always tracked along the growth curve at the 95th percentile, this weight represents normal weight. It is unrealistic to expect this child to fall to the 50th percentile. While traditional definitions would classify this child as obese and unhealthy, this may not be the case, your doctor can help determine this. This child may be just be genetically endowed to be large (here it is useful to consider the size of parents). For many healthcare professionals, this is a radical statement. It is much easier to rely on a “calculation” to tell us if a child is overweight; we disagree. 

On the other hand, a child who has always predictably grown along the 50th percentile for weight, and suddenly shifts upward to the 75th percentile has gained excess weight for that child. A traditional approach to obesity would classify this child in the normal range, and not recognize that the child has gained excess weight for him. Thus, if we look at each child as an individual, we can pick up excess weight gain trends early, long before the child is classified as overweight or obese. Even though no one would say this child is obese, clearly there is cause for concern!