I completed Insanity a month ago. It was grueling :wtf: , but very rewarding. I lost only about 6kg, but weight loss was not my primary focus. I never followed any form of diet, so I am happy with the weight I lost. I was very worried about doing Insanity since it revolves around plyometrics and I already had 3 knee surgeries in my life

. I simply adapted the exercises by modifying a lot of the jumping to protect my knee. I was still able to do more than 90% of the exercises without modification. Also, after completing the first 30 days I quickly realized that I am not ready for the next 30 days. So I repeated the first 30 days until I felt fit enough to continue.
You should be careful with plyometric exercises. I would always advise to rather err on the safe side. Injuring yourself is not worth it. I am currently beginning a revised combination of Power Half Hour, Power 90 and some exercises from Insanity. At this moment I have the flu, so I am just waiting to recover.
I must, however, say that it was one of the best things I did in my life

. My life improved remarkably after completing the course. I was reaching the point in my life where getting up, bending over, laying down on the floor and getting up again or sitting on my haunches become uncomfortable. Now I am able to do those things with gusto. Keep at it, you will be grateful, but remember to listen to your body.