You should not drink diet coke. For my first month, I drank diet soda and only lost six pounds. In my second month, I did a "clean" atkins diet which means, no diet soda, no splenda, only organic stevia and for that month, lost 13+ pounds.

Lately, I've been stalling, and I noticed that I drank "harmless" diet coke a few times a week, and saw my weight would bounce erratically from day to day. I didn't know why when for weeks, I was consistently losing weight. So my advice is, do Atkins clean. Don't drink diet sodas, just water, and perhaps coffee. And you may see an increase and consistency in your weight loss. Good luck.