Those have been my New Year Resolutions for, oooh, years. Some years I achieve them, some I don't. Frankly, in 2010 I more or less did the opposite, ending the year fatter and less fit than I've been for ages - and with fewer words written. Obviously what I should be doing is making my New Year Resolutions SMART.
S - Specific
M - Measurable
A - Attainable
R - Realistic
T - Time framed
Lose weight isn't SMART because it's too vague - how much weight? by when?
Get fit isn't SMART - how do I define being fit?
Write more isn't SMART - more than what?
And none of it addresses exactly HOW I'm going to get there: cut down on the alcohol and ice cream, start going to the gym again, do my creative writing first thing before I blog, email etc. I spent a happy afternoon writing down some SMART objectives until it occurred to me that I could be spending the time writing or exercising - and I'd eaten half a box of Christmas Florentines while doing it.
I think the answer is, if you're going to do it, you will, whether it's giving up cream cakes or writing 1000 words a day. No special resolutions, just do it.