How to do a tekken/street fighter like slider/bar Unity3D : Hi I am trying to create a health bar which transition from healthValueX to healthValueY over time. Curently I am decreasing the value like this:

    void Update ()
    {
        myVar-= 100 * Time.deltaTime;
        slider.value = myVar;
    }
and there is 2 methods which I call on press to manage the slider in addition.

    void addHealth()
    {
        myVar+=250; //Harcoded for the short question
    }
    void forceRemoveHealth()
    {
        myVar-=250; //Harcoded for the short question
    }
I like the transition in the `Update` it looks good. But when I mage a huge change for example in `addHealth()` or `forceRemoveHealth()` I would to color the gap and then to transition instead of go from 300 health directly to 50 for example. 

The tricky part is that I do both - decrease every frame and want to support a bigger decrease based on input. What's the best way to achive this. 