How do you motivate yourself for self-care when you don't feel like it?

I have a great life that is fairly full and rich – I just don’t seem to value basic self-care (like nourishing sleep and food), especially during “down time.”

Do you have any tips for doing so anyway? I often end up staying up late, not preparing healthy meals, instead of doing what I know would support my well-being more fully. I’m sad about that and ready for something else.

I’m more interested in hearing your psychological tips than practical ones. I know what would be better for me; I just can’t seem to get myself to do it. What mindset could I adopt that would motivate me to put in the time and care that I know would feel better?