Chick or Egg

Less Physical Activity: Obesity Cause or Effect?

Does less physical activity cause obesity or does obesity cause less physical activity? It’s a chicken or egg puzzle that many overlook. People generally, and especially advocates for the food industry, are pretty sure that reduced physical activity is a prime cause of the obesity epidemic. New research soon to be published in Obesity shows that the impact of obesity on physical activity is worth a fresh look. Results show that obesity is an important risk factor for declining physical activity.

“Most people talk about it as if it’s a cycle,” said Larry Tucker, the senior investigator on the study. “Half of the cycle has been studied almost without limit. This is the first study of its kind, in many ways, looking at obesity leading to decreases in physical activity over time.”

To study this reciprocal effect objectively, the researchers attached an accelerometer to more than 250 participants. Accelerometers measure actual movement and intensity of activity. Previous studies have relied on less-dependable self-reported data.

The 254 women in the study – of which 124 had obesity – were instructed to wear the accelerometer for seven consecutive days at the beginning of the study, and then again for an additional week 20 months later, at the end of the study.

On average, physical activity in women with obesity dropped by 8 percent over the course of 20 months. This is equivalent to decreasing moderate to vigorous physical activity by 28 minutes per week. In contrast, women without obesity had essentially no change.

Click here to read more from Brigham Young University (where the study was conducted), click here to access the study, and click here to read more about the causality dilemma of the chicken or the egg.

Chick or Egg, image © Juegos olimpicos 2012 / Wikimedia

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