What can i do to lose weight? Beyonce diet cleanse?

I am 5'5" and i weigh 122 pounds. I think i am okay in my arms and legs for how i want to look but my abdominals and i have a little bit like barely of a double chin that i want to go away but i dont know what to do. I eat healthy for the most part but my weakness is pretzels or chocolate. I run, lift weights, or rollerblade (my brother says it wont do anything but online it says it burns a lot of calories) and i want to shed 10- 15 pounds but no matter what i do i cant seem to do it. I wanted to do the Beyonce diet http://www.blackbeachweek.com/beydietplant.html but i heard people can die from it? Can anyone help like some fun ways for cardio to burn fat? Or any cleanses that are healthy that will help me lose the weight i want and that is healthy? Thanks so much!