I've been doing SlimFast for the past few weeks on Alli. I drink a shake for breakfast and one for lunch, and I haven't always taken the Alli pill with them (but someone reminded me that they do contain a fair amount of fat, so I really should, huh?). I've been working out a lot, and I'm definitely seeing results.
I dine out a lot (NYer, and it's part of my job), so I'm doing my best to keep those calories and fat grams down at dinner or when I have to go out for lunch, but it's difficult when my date is feeding me chicken liver mousse on toast. :) SlimFast during the day or whenever possible does seem to help. I don't snack on the SlimFast bars; I try to snack on carrots & low-fat hummus, blueberries, etc.
Good luck!!!