Really you could use just about anything. I suppose my one recommendation would be - make it small enough that it is convenient to slip in your purse so you can carry it with you. A diary with one page per day might be nice. You could use any type of "planner" - doesn't have to be specifically "designed" for diet and/or fitness tracking.
Goal 1 - break 200 (46 pounds lost)**DONE**
Goal 2 - leave obesity behind (BMI 29.9, at 185#) **DONE**
Goal 3 - BMI = Normal (154# or less)
| current weight: 172.5