I don't believe in this 'New Year = a New You' bullshit.
There is nothing magical about a new year, you're still going to be the same asshole you were in previous years. Prince Charming is not just going to suddenly appear on your doorstep. You are not going to miraculously drop 100lbs.
Change does not come easy, overnight, or without sacrifice and dedication. You make a lasting change when you are ready to do what is necessary...& stick to it, no matter what.
For me, it was seeing myself in my college graduation pictures...& the pain I felt in my back and lungs when I tried to walk around campus. I knew something had to happen. I made massive changes to my eating habits, and started exercising every single day. I've lost 70lbs...over 3 years. I have had moments where I've struggled...but I've pretty much stayed consistent & unyielding in doing what I know I HAVE to do. That's what it takes to change.
Only around 8% of people who make New Year's resolutions actually stick to them. I think it has a lot to do with the types of resolutions made: massive, expecting miraculous results. Start small. I started my weightloss off with exercising 10 minutes a day & no fast food...& worked up from there, over time. Baby steps. Also, once the 'high' of the new year is over, and the usual monotony of every day life sets back in, many find it hard to stick to the necessary alterations in lifestyle. Instead they slip back into the familiar easiness of their old routine/bad habits.
I don't make New Year's resolutions. Not that I don't think there are things in my life that need changing...there are PLENTY! I just know that I'm not going to change until I'm ready. I've made 2 major lifestyle changes over the last 5 years, & I've stuck with both...but only because I was ready, & willing to work my ass off for it.