Nowadays, I don't 'plan', per se.
I just eat what I feel like doing so at the time. No regime there, either, just have something when the mood takes me, be it 4pm or 10pm!
I tend to shop, if, & when the need arises. As long as I've plenty of fresh fruit, & veggies at home, I can 'whip up' a small meal, as desired.
Was looking at 'Recipe Yum' last night, which gave me inspiration to cook, in small casserole dish, some spuds, onion, tomato, & chorizo, layered, & just covered in veggie stock.
I really enjoy this simple type of meal.
Other 'stand-by's' are Salmon & Rice Kedgeree, so simple. Also, spud, onion, sliced cabbage, with chopped chook pieces, in chook stock.
I certainly apply the 'KISS' principle!