marla mccants , from nashville , tennessee , began rapidly gaining weight after her ex-boyfriend kidnapped her and held her hostage .
the 43-year-old travelled to houston , texas , to meet with weight loss expert dr younan nowzaradan , but faced death after a blood clot moved to her lungs .
the mother-of-three underwent gastric bypass surgery , but refused to get out of bed for weeks after the procedure .