Here's the homework. We're working on motivation, and this is loosely adapted from Holly Lisle's "The Writing Craft". Sure, sure, what does writing have to do with losing weight / getting healthy? Well, they both require lots and lots of motivation.
This is NOT exactly her technique, she goes much more in depth in goal setting and motivation, and anyone interested in the full material should sign up for her classes (I'm taking the "How to Think Sideways Course" now).
If your goal is to lose weight, and you're having problems motivating yourself, staying on track, etc., it's pretty obvious that there's a part of you that really doesn't want to do it. You're getting some kind of benefit out of NOT doing it. You need to figure out what that is.
Take two pieces of paper, and a pen or a pencil, and a clock or watch you can time yourself with.
Take five minutes, and on the first piece of paper, list all the benefits you would get out of achieving your goal. This is a stream of consciousness exercise. Get started, and anything that pops into your head for this goes on the piece of paper.
Then, take five minutes, and write out all the benefits you are getting out of NOT working for your goal. Maybe it's things like "I don't have to waste time working out." Or, "I don't like the feeling of sore muscles." Maybe it's "breakfast tacos!" Whatever pops into your head.
Once you've got them both down, take a hard look at both of them, and ask yourself which list is more fulfilling.
You don't have to share this with anyone, but it's a very interesting exercise, and can help you figure out why you're sabotaging yourself.