I have been successfully using both the app as well as the website from myfittnesspal to loose weight. Some of the features are that you can add friends kind of like on facebook to your account, who will like your achievements. What I have been missing a true gamification. Give me 1.000 points for staying under my kcal maximum. Give me 50.000 points for loosing a 1kg of weight. You get the point.
As part of the gamification of weight loss I would also like to suggest you get either a step counting app like Google Fit, a smart watch or a fitness band. All these also lack the point and merit based rewards required for true gamification. All I did is give myself a goal (12.000 steps a day, less than 1.000 kcal a day) and reward myself for it (pat on the shoulder).