It is neither good nor bad it is pineapple juice. It has calories and other nutrition. Since it has a lot of calories, you might prefer to eat something with fewer because it will be more filling.
To loose weight: eat a balanced diet, eat less, and exercise more.
To keep the weight off, you should loose about 1 pound per week.
http://www.consumer.gov/weightloss/setgo...
http://www.nlm.nih.gov/medlineplus/weigh...
http://win.niddk.nih.gov/publications/in...
http://www.mypyramid.gov/
http://www.exrx.net/
http://www.jacklalanne.com/biograph.html

Yes! Try the natural kind. Less sugar. All natural sugar is healthier.

I haven't heard that it's especially good..but I doubt it's bad either!

It can be if it doesnt have a lot of added sugar. 100% juice is the way to go.