Question

Great question with a relatively easy answer.  Just move.  Squats, chair squats, lunges, stairs, assisted push ups (like off a counter top), pick heavy things up and put them down.  Do it repeatedly and consistently, and you'll be burning more calories versus just sitting.  In fact, stand when you would otherwise sit. Bottom line... MOVE!

Now to the more important part... Get out of your home and walk.  Put on headphones and listen to uplifting music (I love Handel, Haydn, Mozart, Beethoven, Bach, etc., but you may like jazz, rock, or rap...  what ever it is- it must be positive and uplifting to you!) and go outside and walk.  Hold your head up high, smile, feel the music, be grateful for the ability to walk, and walk like there is nothing that can stop you.  Develop an uplifting incantation that you can repeat to your self over and over again as you walk.  It can be a prayer, mantra, phrase, quote, etc.  But it must be something that you can say and FEEL as you walk.  For example, one that I used to motivate me when I was having a hard time was simply "Every day, in every way I'm getting stronger and stronger" and I just keep adding more things... "Every day, in every way I'm feeling more and more happy" "Every day, in every way I'm getting better and better" On and on I would recite out loud these kinds of incantations (and many more)... and still do decades later.  And yes, you must do them out loud!  If I could do it before cell phones, then you have no excuse why you can't do it now. Everyone will simply assume your are on the phone.  You are going to become your own best friend to yourself who motivates rather than critiques, who inspires rather than shames, and feels immense gratitude rather than depression.

Finally, the most important part... After working with hundreds of women I've learned that in general (you may be an exception) when there is a woman who is very obese, there is often trauma in her past.   If you have trauma in your past (psychological, emotional, sexual, and/or physical) I highly recommend you work with a great person to get you out of the self defeating trance you are in.  This person may be a priest, minister, rabbi, psychologist, hypnotist, or simply a wise friend.  But the deeper issue that brought you to where you are today, the issue that causes you to make bad decisions when you know better - must be dealt with. Then you can free yourself from your self imposed limitations, and allow the fit, joyful, and grateful girl inside shine and help others.

Good luck and God bless