May, it would depend on what you were looking for - Do the Atkins shakes have enough protein? You'd want at least 20g a serving. If they come in powders that you mix then you can always mix 2 or more scoops to make up the right amount of protein.

As for the bars, if your intention is to do this LC then I'd forget about them - most have hidden carbs, if not all, and they can actually be closer to 15 - 20g per bar. They also don't taste all that good A search on this site (top right of every page - it's the globe icon) for "low AND carb and Bar" will give you some idea of just how deceiving the name "low carb bar" actually is.

Best of luck!
Nat