Hi Bookworm. CS is a partial meal replacement but you have 2 shakes 3 approved snacks and a balanced meal. Obviously all very low portions and low carbs but it means you have something practically every 2 to 3 hours to keep your blood sugar stable apparently. I have lost a significant amount on it in these last few days to be honest it seems unreal to say it and am not going to until I get to Saturday. 