@Isaac
If you're metabolically healthy, which also means your blood sugar is well regulated, eating 3x a day is just right.
But if you have blood sugar issues, then eating more often, is needed.
I don't necessarily have to eat more, or less, for any meal. I eat as much as I can until I'm sated. And I follow what my body says is enough.
But it is what works for me. My basal metabolism is such that I don't gain weight even when I don't exercise a lot. I'm not stuck in a cubicle either and the day goes by with me easily being active with housework, repairs, cooking, and mental activities like reading, writing, and solving problems. An active brain uses a lot of energy, and I find it more enjoyable than walking thru a boring neighborhood.