Anyone can do anything for one day....and sometimes for just a minute.
You wouldn't ride your bike for a week solid without every getting off the bike. When your riding your bike do you tell your self...I can do one more block just for today.
Now I use that for changing my lifestyle as well. Just for today I am choosing fresh fruit over the chocolate eclair.
Just for today I am choosing the stairs over the elevator. Soon it all becomes new habits and the old ones are gone!