There's one thing that keeps most of us from losing weight: ourselves. We all know we need to eat right and exercise, but it's those mental blocks that keep us from taking off the pounds for good. So here are three mental weight-loss hurdles and how you can get over them, from the folks at Fitness magazine. First hurlde: When you don't see instant results you give up. Almost 40% of people will ditch a new diet if they don't see results in two weeks. However, that's not a sustainable way to lose weight says Dr. Stacey Rosenfeld. She's the chief psychologists for the New York City Triathlon. According to Rosenfeld expecting too much from a diet creates a cycle of deprivation and overindulgence. Here's the fix: don't make weight loss the ultimate goal. Instead make working out a certain number of times each week, or eating healthier foods the goal. That way you'll get that sense of accomplishment every day, instead of losing steam when the scale doesn't do what you want it to. You're afraid you won't be able to keep it off. It's common to worry about failing at a diet, especially if you've tried in the past. This fear can easily become a self-fulfilling prophecy. You think you'll fail so you just stop trying. How do you get past the fear of failure? Sofia Rudin-Grey is a clinical psychologist at the Duke University Diet and Fitness Center. She says you have to tell yourself that there's no such thing as failure. When you mess up and eat a bag of chips, don't beat yourself up. Look at the situation and ask what triggered the snack attack. Once you know what caused it, you can come up with other ways of handling those situations in the future. * The last mental weight-loss hurdle: You haven't faced up to what made you put on the weight in the first place. This is a biggie. More than half of women say they eat to distract themselves from the negative issues in their lives, but those problems don't disappear when the pounds do. Instead, find a more positive outlet for your emotions, like exercise. It lowers stress and boosts endorphins. Even though it won't solve the problem either, it'll make you feel better while you're figuring out what the big issue really is.