The answer to your question is discipline. To have weight loss you have to change your eating and behavior habits to something that will benefit what your trying to accomplish. You need to develop your style of eating that causes weight loss, have the discipline to stick with it and THEN have the discipline to maintain your weight. When you find the style of eating that suits you ( your metabolism ) and has the desired effect of weight loss, and no gain of any weight once your goal is met, discipline will get your there and will keep you on track.Learning about food and how to feed yourself correctly is also very important. However the difference between knowing and doing is the big D - discipline.
Let's face the truth and agree that in this day and age it's tough to lose weight. Yea, it's tough and that's exactly why people don't ever reach their goals or if they do, after a period of time they regain because they don't have the discipline to follow a certain eating regimen regularly. This fact alone dooms most people.
You can make any excuse you want to but that is really what it comes down to. Either your weak or you strong, either you want to succeed or you don't. The secret is discipline.
Fortunately there is plenty of help around to help you succeed but all the help in the world won't get it done for you, YOU have to do it and it takes the big D to get it done.