How to gain weight on zerocarb starting out?

I have a high metabolism and am naturally skinny/very low body fat, and am currently underweight as a result of autoimmune issues preventing me from exercising. The only way I gain weight is lean body mass when I’m lifting weights regularly. I’m want to start zerocarb to help autoimmune issues, but I’m worried that I’ll lose what little bodyfat I have, since most people seem to report weight loss in the first month. How can I avoid this?

from Zero Carb Zebras http://bit.ly/2R1q810
via IFTTT