WeightChart Trackables have been rolled out during past few months. In addition to your weight, notes, and feeling indicators, WeightChart trackables allow you to start tracking nearly anything. There are predefined trackables for glasses of water, blood pressure, glucose, etc. But, it is quick and easy to define your own trackables.
Until now, you could only see the Trackable values in the table view. Now, you can add graphs of the Trackables to visualize you progress. This is a great addition; try it!