It's definitely good to live in the moment and not stress yourself out over what tomorrow will bring. On the other hand it is wise to be prepared so you can achieve your goals for tomorrow. That being said, I too am soon to have take down after waiting over a year to have it. For me I feel it is important to nourish my body with healthy food choices, supplements and exercise to prepare my body for healing. I would rather go in feeling strong, healthy and ready than to feel bloated and tired.
All the best with your up and coming surgery.