Track What Matters.
In 2008, I entered my freshman year of college. One of the very first things I learned from my General Business 101 professor was something from Peter Drucker: you can only manage what you can measure.
Quantification is powerful. It takes something from the ether of our Universe and applies something material to it. In this case, a data point.
Tracking enables you to determine whether or not you're on course for whatever it is that you want. The only way to know if your body composition is changes is to track you weight, circumferences and body fat percentage. Without these, there would be little way to know.
A heightened sense of awareness also comes from tracking and measuring. When we track what we eat down to the gram (i.e. macros), we begin to learn exactly how much we're actually eating.
Like any change, it can be difficult at first. But with consistency, persistence, and effort, the new habit quickly takes hold and the benefits are almost immeasurable (almost!).