I am just plain lazy.
I have lost almost 75 pounds this year and I still do not exercise. I need to at least learn to walk regularly in the street or the gym or around the mall, but some place!!! Why walk? The benefits of walking:

1. “Burn” calories, improves the rate of metabolism.
2. Helps strengthen the body, reduce local subcutaneous fat, helps to restore the loose body areas, as a result of the weight loss.
3. Helps to strengthen the bones (something especially important for women).
4. Reduces symptoms of varicose veins, helps the circulatory system.
5. Reduces blood pressure and pulse when you are relaxed
6. Help overcoming headaches.
7. Helps you be calmer with less stress, “intensity”, “nerves” that often cause greed, need for food.

After a good walk you would feel better, more relaxed, less stressed, and less “need” for food.

(info 'borrowed' from http://www.weightlosshelpandtips.net/2009/03/weight-loss-exercise-tips/ )