Magical thinking is the problem that most people have. Far and away the top so-called "resolution" of people polled is to "lose weight" .... so long as they have to do absolutely NOTHING to accomplish it.
When people tell me that they want to lose weight I usually advise that they start by drinking nothing but water (or unsweetened tea). That right there is usually enough to deter most people from losing weight. "But I LIKE soda...", they tell me. I don't even bother to explain to them that they don't actually know what they like because they have been programmed by thousands of hours of television advertisement to believe that they "like" whatever Coca Cola and Pepsi tells them they should like. So, as an alternative, I tell them "then only drink diet sodas". "But I DON'T LIKE diet sodas". That's why you're fat. Because you're not even willing to do something as simple as drink water or diet soda. Of course some of them repeat the "artificial sweeteners give you cancer" bull$hit urban legends constantly repeated by the sugar and corn syrup industries. First off, there are sweeteners like Stevia that are completely natural (not that this proves its healthy), but even sweeteners like sucralose or aspartame, no matter how bad you might believe they are, are better for you than the alternative which is obesity causing, calorie rich sugar and corn syrup. Oh, I know people want to believe that "natural" cane sugar is "better" than corn syrup, and maybe it is on some level, but you still don't want either one. There will still be the equivalent of 16 teaspoons of sugar or corn syrup in your average "Big Gulp" and you shouldn't be eating that amount of sugar all day, not to mention just at one meal, or several times a day.
Bottom line, if you want to lose weight then you will have to do something. You have to give up something. You have to make some kind of sacrifice, compared to your normal routine. If you can't even give up drinking high calorie sodas, then you will never have the discipline to take things any further and lose real amounts of weight.