Loving yourself is the key to doing anything.
When you love yourself, you respect yourself. When you love yourself, you have confidence to do anything you wish to desire. When you love yourself, you know what you like, dislikes, your boundaries, strengths, and your weaknesses. Love can also help you be patient as well. This is the first key to a lifestyle change.
For me, I never liked myself because I was obese. I thought the world is based around our shells where our souls hide in. I was never confident either because I always gave up and I always hide in my room so no one could look at me. I knew I had a problem, but I never figured it out for the longest time. My mom had the weakness on her too, and I realized that she was a mirror to see why I couldn't do anything. It was hard though, I always gave up trying, but it took a good loving friend who pretty much drilled into my head that I was awesome and never left me alone about it.
Once you start loving yourself, your eyes start to open and you realized that there has to be some changes made. You know it, and that is the first step into changing yourself for the better.
Loving yourself is a patient on going process. It gets stronger over time, but that is if you keep it up. Don't let the negative thoughts tear you down. Instead stand up to them saying. "Hey! Now that was disrespectful! I am a beautiful person who just has more potential to be even more beautiful! Don't give me that crap saying I am ugly and don't deserve anything."
Your brain's self-talk is your worse enemy in these cases. So teach your brain by saying things like: "Hey, I know you have struggles accepting our body, but you know, things will get better! We just have to take it slowly." You have to be friends with your brain, but you also have to correct it too.