Good start. Please make sure you drink warm water as per thirst, stay warm and rest plenty. In your case you can walk 20 minutes a day.
Don’t take any supplements, your body will make all it needs from fat and other junk. Your goal is hefty, however, if you stick to it you can reach that goal.
Please watch Dr. Fung’s videos on Youtube. Also watch Dr. Goldhamer, he treats all his patients with water only fast.