Physical Activity & Childhood Obesity

Let me be very clear: there are many benefits to physical activity. It appears, however, that fighting childhood obesity is not want of them.

This meta-analysis recently published in the Canadian Medical Association Journal, demonstrates that school-based physical activity programs had no significant influence on Body-Mass Index (BMI). This is surprising to many who claim that lack of activity is the cause of an epidemic of obesity. The authors make the following point:
"The association between reduced physical activity and obesity has been well established. However, there is no conclusive evidence that reduced physical activity is a causal component in the pathway leading to childhood obesity. Rather, there is evidence to suggest that the observed association may be a downstream effect of obesity."
In other words, kids who are overweight are less likely to be active. This can compound their problems by leading to a decline in other health indicators that our linked to activity. One of the most alarming findings in the past number of years is that many obese kids show muscle loss and fatty infiltration of muscle that ordinarily does not show up until well into adulthood.

There are two main issues that I want to point out here:
(1) Body-Mass Index is not an ideal measure because it does not account for differences between fat mass and lean muscle tissue. One thing that may be lost in this overview is that muscle may have been gained. Resistance training would be a far more effective means of achieving this, but kid in the "growth phase" of life may add muscle more easily than adults who need to work harder for such gains. The challenge of the activity would be an important factor in this regard.
(2) Nutrition is, by far, the most important element in achieving fat loss. Put simply, many kids eat way too much simple sugars and starches for their body to do anything else but store fat. Food choices and portions have significant impact on hormonal responses that set up a slippery slope to obesity.

I highly recommend the book Strong Kids, Healthy Kids by Fred Hahn for those wanting more insight to these issues. It is a great book about a very serious issue. Here's my summary: Build muscle. Eat less sugar - way less. It can be that simple.