Hi ya!

For Atkins induction on only 20g of carbs it will be hard to keep up an intense weight routine for very long... your body needs the carbs for energy in the gym.. it cant be fueled for weight training on the fat it is burning... Many people in this forum are doing exercise routines such as BFL (Body for Life) on a Low Carb eating plan.. but they are eating anywhere between 40 and up grams of carbs per day.. depending on the person and the intensity of the workout.

To understand more about the effect of carbs, carbing up, ketogenic diets.. etc.. check out this link...CKD 101

the CKD plan explains some of what you are wondering about.. I am not saying this is a plan you should try necessarily, but more just suggesting it as a reading resource for you to understand what muscles actually need for growth and performance in the gym.

hope this helps someone out there!!
j