I rejoined Spark a few weeks ago after not checking in for about a year. I put on 8 pounds in the interim -- and since coming back I have lost 2.5! I knew that would happen. I'm not even tracking everything in detail. At this point just checking in once a week keeps me mindful enough through the rest of the week about my activity and what I'm eating to help me stay on course. :-)
By the way, I feel like I should say that it wasn't always like this for me. For a long time using the daily food tracker for every meal and for all my exercise was really useful and important. Those trackers are great tools and worked really well for me when I first joined.