Body Mass Index (BMI)
The measure for Body Mass Index (BMI) – height/weight ratio – seems to be less reliable since the measure cannot distinguish between muscle mass and fat mass for each child. Studies from other interventions have used BMI as the gold standard of measuring overweight and obese children because they hadn’t matured yet – muscle mass should be similar based on child development stages. What we are finding is that the LiiNK children may be developing more muscle mass just based on the increased physical activity and outdoor exploration daily. BMI may not be the best measure for these children even at 5-8 years of age. We are now using a bio-impedance scale in pilot studies to assess any differences between BMI and body fat/muscle mass percentages.
Over one year in the project, 14% of the LiiNK students shifted from the overweight/obese category to the healthy weight category, while only 2% of the comparison students reflected similar changes. After tracking BMI across three years, LiiNK students continued to reflect a 7% difference over the comparison students from the overweight/obese category to the healthy category.