What causes obesity?

My belief is that the 10,000 steps per day can be a key factor in reversing the obesity epidemic. What causes obesity? This is an important question, of course. I found a good lecture by a medical school professor, Dr. Henry Sanchez from the University of California, San Francisco. He explains the factors leading to overweight and obesity. Dr. Sanchez did this lecture for University of California Television (UCTV). Here is the YouTube link:

Metabolism and Nutrition: The Inside Story of Obesity

http://www.youtube.com/watch?v=oSBBx6ZAciU

Just recently I discovered the importance of working at a brisk pace. My goals now are to take 10,000 steps per day, including one hour of aerobic walking. Today I walked at an aerobic pace for 66 minutes and covered about 4 miles (8,000 steps).  Errands and daily activity easily add several more miles throughout the day. I am able to reach 5 miles (10,000) steps as my baseline for good health, including a good amount of aerobic activity-- and hopefully some weight loss.

Here are my stats for the last four days of pedometer work.

date        steps         distance         aerobic steps   aerobic time     steps per min.
Dec. 3      4,449        2.10 mile        4,152               38 minutes        109.3
Dec. 4      9,898        4.68 mile        8,453               82                      103.1
Dec. 7      9,836        4.61 mile        7,312               64                      114.3
Dec. 8    10,147        5.12 mile        7,910               66                      120    

As you can see, I did pick up the pace!