I was doing a bit of browsing and found this on the Atkins forum, and I think it makes sense, ( with my understanding of the skinny rules - remember I don't have the book so excuse me if I have interpreted it wrong) just took a snippet as follows:
Found this on another forum - really good post
1. Sodium - Limit consumption of products loaded with sodium such as bacon, ham, sausage, salami, and hot dogs. The preservatives (sodium nitrates) used give these products a longer shelf life but eaten in quantities, they will cause water retention in many of us. If you eat bacon for breakfast, sausage for lunch and ham for dinner, you may wonder why you've stalled even though these foods are low in carbs. Salt will hold onto water for dear life. The more you eat, the more it holds onto water. If a prepared food has a long shelf life, it may have a lot of added salt preservatives.
2. Water - The proper amount of water to drink is until your urine runs clear. There's no magic amount, like 72 oz per day. It varies too much based on your body size, amount of exercise and sweat and other factors including what you eat. The darker your urine, the more deficient you are in your water intake.
3. Water Substitutes - A lot of people don't like drinking water. The only possible substitutes I know that pretty much count as water is club soda (no sodium) and spring water. Note that tonic water is not the same as club soda as it has sweeteners.
4. Sweeteners - Though sweeteners may claim to be 0 carb and 0 calories, they cause weight gain. I've come to learn it doesn't matter what brand of sweetener it is, whether it's aspartame, splenda, stevia, or sugar alcohols. These sweeteners will spike your blood sugar, increase the amount of insulin your body produces, and the extra insulin gets stored as fat. The 1 month I started drinking diet soda again, I gained 9 lbs more that month than any average month, despite intense exercise and keeping my diet the same as the previous 16 months. This extends to more than just diet soda, it includes crystal light, sugar-free jello, Atkins bars, Atkins shakes, tonic water, and possibly even chewing gum. You are limited to 3 servings of fake sweeteners per day on Atkins. The less you consume, the better it is for your weight loss.