When I most noticed it was during a cruise... I didn't exercise and I ate like a pig (like 2 dinners a night), and nothing happened. At the very least my pants should have fit a little tighter. (Everyone else I was with put on a couple pounds.)
I was using Tonalin. Some from Kilosports.com, and NOW brand from 1fast400.com (which isn't officially Tonalin, but the content is the same, I think).