you're weightloss will be a combination of things.
when i started SW i went for a 1.5 hour walk and 2 x 1 hour swimming sessions and i lost 1lb - wasn't impressed! but last week i played golf for 2.5 hours and did a 1 hour swimming session and lost 3 lbs.... but this week i have done no excercise at all and lost 4 lbs!
i've lost the majority of my weight doing no exercise... but some weeks i do 3 or 4 hours. i work different shifts each day, so struggle to fit it in - mainly because i'm disorganized! towards winter i will get a gp referal for my local sports centre, as i was offered one last week, but said i'd come back at a later date.