Be fully energized, fully hydrated and healthy.
Eat some Zucchini or Pumpkin so you get your character to vomit.
Observe as your healthy status disappears and your hydration level changes to dark green.
Hydrate and energize yourself so you are always light green energized/hydrated.
Play for more than an hour and notice that you can't get the healing status visible and thus healthy won't ever appear again.