Hi Rich, I am new to Atkins but have spent hours and hours identifying the "rules" of the plan and keep finding things I should or should not have been doing as I reread the chapters. No caffein, No aspartame, make sure to drink your water, No products that contain sugar even it they say no carbs! Can you think of any changes in your eating habits you have made since you lost all that weight? Perhaps a product you are still consuming but that the product has changed and you didn't notice. Good Luck on your getting back to success in losing...Judy