I find that I get constipated when my fat % drops to 50%. As long as I stay above 60% fat, I am regular. I still may only go every 1-2 days, instead of 2-3 times daily, but I think my body uses the food, instead of making waste. Go by how you feel though. If you feel bloated, gassy, and like you need to go, but can't, then definitely try some fiber. Just read labels. Some have a lot of carbs, and some even have sugar. You can add in some nuts, or oil, or eat the skin, or even change chicken to dark meat for more fat, if you want to try that.
I would fill out your tracker and see how many carbs - fiber you eat over 3 days to get an average. You may be well over 20 grams, and still losing. If you are at 40 NET grams for example, and losing, then just make sure you eat 40 NET grams a day. The only worry about calories is that you just go crazy on them, which doesn't really happen after the first week. Since you aren't starving, just eat till full. You probably need to make sure you eat 3-4 meals, more than worrying about OVEReating.
Russell - current BMI 28.6
197 - bmi 30 - done
164 - bmi-25
| current weight: 181.0