Personally, I would say Intermittent Fasting is the best health tip! I've done it for several years now and wish I knew about it 10 years ago. Basically dinner-time becomes the new breakfast. It's difficult to get used to it initially but feels amazing once you get the hang of it.
I did a small write up here if you want to read more: https://steemit.com/health/@bmicalculator/intermittent-fasting-is-it-healthy