While it’s a nice thought, it is not always feasible, especially if you have a deficiency (certain medications & substance can actually deplete/leech your magnesium stores).
If you are low, take supplements for a while. Less than a month before transitioning to magnesium-rich foods. I’d suggest magnesium taurate or magnesium glycinate. Magnesium oxide actually absorbs horribly, so you wouldn’t be getting much from taking it.
I’ve had a deficiency years ago and was unaware of it. Caused so much jaw tension that I ground down my teeth while I slept and fucked a lot of them up. Also had a lot of headaches and muscle tightness that completely disappeared after taking supplements.
Do what’s best for you in the end, but be cautious. Also please consult a medical professional before adding supplements or anything of thst nature to your regimen.