It's hard not to compare yourself with others--"why can she eat that and still be so thin?"--and wonder why you are cursed with a body that constantly betrays you by being heavier than you'd like. These thoughts and habits lead low self-esteem and self-loathing. I remember having a conversation with someone close to me one time, and he was telling me how he looked in the mirror and saw how heavy he had gotten. He just stood there and berated himself and told himself how disgusting and ridiculous and weak he was...and this is how he motivated himself to TRY to lose weight (it hasn't happened yet).
Is it any wonder we can't accomplish the things we want when we are so hard on ourselves? You wouldn't repeatedly tell a child how stupid and hopeless they are, and then expect them to be a gifted student. Likewise, you can't expect to be able to transform your body to be healthy and strong while constantly telling yourself how gross and weak you are.
The first step to lasting health and weight loss is to change your relationship with YOU. Practice learning a new "self-speak" and focus on the things you love about yourself. It will take some time and patience, but you can eventually learn to only say positive things about yourself. A good way to stay on track is to ask yourself if you would say to someone else what you are tempted to say about yourself. Would you meet a friend for lunch and said, "Sally, you look so fat in those jeans!" or "God, you've really let yourself go!" Probably not! But you likely say similar things to yourself all the time.
Remember that if you can silence your own worst critic--YOU--you will open the door to long-lasting, positive change. Make a point to only allow positive thoughts and compliments when thinking about your body. I also find it very useful to have a mantra that I repeat to myself over and over. It may sound silly, but it really helps. Here are some examples:
-I am a strong, beautiful woman.
-My body is healthy and fit.
-This excess weight no longer serves my purposes, and I will let it go.
-I am smart and beautiful and worthy of perfect health.
It also helps to have a vision of yourself in the perfect body, doing something you really want to do. For example, if you've always wanted to run a marathon, picture yourself in cute running shorts crossing the finish line. If you'd always wanted to wear a skimpy bikini but never felt confident enough, picture yourself relaxing on the beach in the perfect bathing suit. These images can be hugely motivating and help you see a different reality for yourself.
Learn to be your own biggest fan!