Ok so ya most of us arent in the right shape 
lol or even qualified to really advice most of the celebs but ya watever…:). Just from what we have observed lets come up with suggestions for celebs…;
Kareena- i have seen in the latest pics that she has put on lil weight…which i think was much needed but i think what she needs to do is keep toned.
Priyanka- thanx to her face cut she managed quite well with her, newer thinner look. Her only issue is that her shoulders r bit weird lol i dont know if i am the only one who noticed it but she is kinda broad on the shoulder and have a contrasting waste line which looks very weird in some dresses. So ofcourse since she cant or rather wudnt do much abt her tiny waist what she should do is minimise wearing clothes that highlight her shoulders…
Katrina- She is lil big down waistline so she needs to stop wearing anything that highlights that part. She looks lovely in sarees and gowns.
Vidya- if you dont like going to gym than just wear shalwar kameezes :P.