The Science of Fat

Nature, nurture, or just plain hard work?

By Holly Wyatt, MD
WebMD Weight Loss Clinic - Feature

Reviewed By Charlotte Grayson, MD

There is an ongoing debate among researchers who study the causes of obesity. It's the old "nature vs. nurture" question: When people who are obese lose weight and then regain it - sometimes over and over again - what or who is to blame? Does genetic inheritance doom us to the boom-bust cycle of diet, relapse, diet? Or is it a failure to make and maintain the necessary changes in one's diet and exercise routine?

When people ask me, "Why are we facing this obesity epidemic?" my answer is that it's really a combination of factors. Physiology definitely plays a role, as does genetics, and there are undoubtedly certain people who are predisposed by their physiology - by the way their specific bodies work - to gain weight more quickly than others, or have trouble losing weight and keeping it off.

Bodies at Rest

Our basic physiology - the way the human body functions - hasn't changed over the last 50 to 100 years, yet during that time we have seen an alarming increase in obesity in our society. What has changed is our environment. Once we were a nation largely of farmers and laborers; now we are a nation of office and industrial workers whose lives have been made easier - and less active - by technology. In addition, millions of us live in neighborhoods that are designed for drivers, not walkers. We park as close as possible to the mall, take the elevator instead of the stairs to go up one or two flights, and drive to the corner store rather than walk because we're in a hurry.