My husband and I have been Atkinsing since last September, including a trip to WDW/4-night Wonder. He's just moved from Induction to Ongoing Weight Loss, while I'm basically on Maintenance ever since I found out I was pregnant

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While we were in Induction, we found the Advantage Bars to be invaluable for that midafternoon slump. One of those and a huge glass of water would carry me through to dinner time. Neither one of us had trouble with that knocking us out of ketosis, though.
Like others have said, the muffin mixes are pretty good. I especially liked the Banana Nut one--if I'd had it right after having "real" Banana Nut muffins from a bakery, I probably would've hated it, but after a month or two of Induction, it was wonderful!
We go REALLY light on the Endulge bars of all flavors; usually only eating half a package at once, because those do tend to slow us down.
The chocolate, strawberry and almond syrups are a major standby (we started ordering DaVinci ones online)--mixing them with club soda and a shot of heavy cream makes a GREAT treat. We have one of those almost every night. Those are just the flavors we like--DaVinci makes something like 20 or 30 different flavors.
We also take the Atkins supplements (okay, I'm taking prenatal stuff now, but I did), especially the Basic #3, Essential Oils and Dieters Advantage. We added Chromium Picolinate and Potassium from the local grocery store too. The supplements really seem to make a difference--if we forget them, our bodies let us know.
I found really good prices for all this stuff at several online vendors. I'm not sure if I'm supposed to post that stuff, so if you want to PM me for details, I'd be happy to give you a list.
We were quite unimpressed with the Baking mix (though I use it to dredge various cutlets with before sauteing), as well as the pancake mix and especially the pancake syrup. Bleah.
I make cheesecake flavored and sweetened with the DaVinci syrups every now and then and that makes a nice treat. Especially with some homemade whipped cream...yum!
Someone else mentioned the lowcarbfriends.com website--it's very good for recipes (I like Beachgirl's Cheesecake best, and I tried several). I collected some of my favorites from there and other websites in a Word doc and would be happy to mail it out by request as well.
I've found Wal-Mart has good prices on the Carbolite stuff, which makes their candy in particular more affordable than the Atkins Endulge stuff. But I like the Advantage bars better than any of the other low-carb ones I've tried.
Good luck!
Joye