Carbs and calories; red meat and breads are a very good source of both, also, proteins such as are found in nuts.
Cold sores are a result of the body's chemistry being out of balance, this is easily remedied by taking a mild laxative such as Correctol, this will balance the body chemistry and the cold sore will dissappear.
Hanging in the balance means that the answer or solution is not quite clear and other factors may need to be investigated or researched. In short, the outcome could swing either way and so is literally balanced between two potential outcomes.
You may use motion sensors for outdoor lighting. Sound activated lighting inside and burglar alarms. You could even have curtains which close when the lights come on !