A lot of times the reason we can't conquer our issues (did I really just say that after encouraging people not to "fight" their issues??!!) is because we play a complicated game of hide and seek with them. We hide our issues from other people and ourselves. We seek to find out what causes our issues, and sometimes we find the answers!.....but then we hide from the solutions. Or we even experience success (i.e. weight loss, quitting smoking, getting in shape, reducing our stress), and then we slide back into our old routine. We rationalize and deny the truth so we can stay in our comfort zone, even if it's not somewhere we want to be.
Think of yourself as two people. One is the person who wants to be the best you can be and knows how to do that. The other is the person who desperately wants to KEEP EVERYTHING THE SAME. We are creatures of habit, and our ego, if you will, thrives on these habits. Your ego "protects" you from seeing the truth. Have you ever looked at yourself in the mirror one day and had some major revelation about yourself ("Oh my God, how did I get so fat....old....out of shape....etc)? Why didn't you realize it while it was happening? The perfect example is a person who is 20-40 pounds overweight, and all of a sudden is in a panic to lose the pounds instantly. But----those pounds gradually accumulated over time, they can't go away instantly. Why didn't we see the extra pounds when we only needed to lose 5? That would have been much more manageable, right?
The answer is complicated , but your brain (a very general term) protects you from seeing change. A study was done on weight gain, and showed that people literally could not see a difference in their appearance when they lost or gained 5 pounds. If you think about anorexia, it's almost like this phenomenon gone haywire. Then consider how gradually most people gain weight---your brain is going to be very slow at realizing how different you actually look.
In my personal experience, men are much more likely to not "see" their weight gain. In fact, I've had 300+ pound men tell me they know they could lose a couple pounds, but they're not fat or anything.
The bottom line here is that you have a few physiological things going against you when you're working on improving your lifestyle because your body/brain is preventing you from fully grasping your current status and also is trying furiously to keep you just how you are. What can you do?
1. Look at yourself in pictures---it's easier to see the truth when you're not looking in a mirror
2. Be honest with yourself when you feel yourself rationalizing behaviors---even if you don't change that time, acknowledge what you're doing.
3. Don't beat yourself up for having a hard time sticking to a plan
4. Make really small changes, experience small successes, and build on them.
5. ASK FOR HELP!