Fatness is the Cause but Not the Effect of Physical Inactivity
We often believe that inactivity leads to fatness. However, a recently published study does not believe this to be true. On the contrary, the researchers found that fatness leads to inactivity!
Childhood obesity is a major cause of concern in a number of countries today. Obesity occurs due to an imbalance between intake of energy (in the form of diet) and expenditure (in the form of physical activity, basal metabolic activity rate of the body etc.). A number of initiatives have been taken up by the UK government to promote activity in children in schools as well as at home in an attempt to control obesity.
A study was carried out to test the association between fatness and physical activity level in children. A total of 307 children of 5 years of age were selected from different schools in the UK for the study. These children were examined once a year when they reached 7 years till they completed 10 years of age.
Physical activity was measured for a total of 4 times in each child during the study with the help of an instrument called the Actigraph accelerometer. The physical activity was measured for at least 5 consecutive days including a weekend day each time.
As a measure of fatness, whole body fat percentage was measured using dual energy x-ray absorptiometry. Body mass index and waist circumference were also measured.
From the selected group, 202 children completed the study.
The study found that, in general, girls have a higher body mass index, waist circumference, body fat percentage and are less physically active than boys. In both, boys as well as girls, body mass index, waist circumference and body fat percentage increased with age, just as physical activity declined.
The study confirmed what was earlier known - that physical activity and fatness are inversely related. Based on statistical analysis, it however states that fatness is more likely to affect future activity rather than a decrease in activity affecting fatness. Body fat percentage was predictive of changes in physical activity, but physical activity was not predictive of changes in body fat.
Similar results were also seen in adults in other studies.
The results of this study should however not be interpreted as physical activity being useless. Physical activity definitely has a positive influence on health and should be encouraged. This study mainly highlights that only increasing physical activity is not the answer to controlling childhood obesity in various government programs.
Several explanations have been suggested to explain why increase in fatness may lead to physical inactivity. Fat children may perceive their bodies negatively and therefore avoid taking part in sports. Exercise in obese children may cause muscle pain, breathlessness and fatigue faster than in children of normal weight.
Further large-scale studies are required to establish these findings and find out the exact reasons for the same. In addition, since diet has been successful in various studies in controlling obesity, studies should probably focus on this aspect in controlling childhood obesity.
Fatness leads to inactivity, but inactivity does not lead to fatness: a longitudinal study in children; Metcalf et al; Archives of Diseases in Childhood 2011