Yes, one can be in ketosis and not lose weight.
Yes, there are benefits to being in ketosis without needing to lose weight.


Explanations and uses for those two statements can be found in the writings of those who author the following blogs, which can be searched. Two are by medical doctors, one by a brilliant veterinarian, and one by a woman who has done a great deal of research for her own health challenges.


http://www.paleonu.com/ by Dr. Kurt Harris
http://high-fat-nutrition.blogspot.com/ by Peter Dobromylskyj
http://evolutionarypsychiatry.blogspot.com/ by Dr. Emily Deans

http://failsafediet.wordpress.com/

Sorry to not give you a quick and easy answer, but, the answers could fill several books.

All the best to you.