I feel I've gained weight like I feel fluffy if I cut carbs I know I'll go down but how do I know how many carbs to eat to still be able to run and lift on a daily basis without feeling devastated afterwards?
I run completely on healthy fats and try to keep my carbs below 25 grams per day (weighing 180lbs/82kg, les than 10%Body fat). Once your body got used to using fat as energy source you'll be fine. It takes about two weeks to switch. Other advantage: you don't "hit the wall" around km 30 anymore as your body won't switch from carbs to fat anymore.