Some macrobiotic practitioners suggest that we only eat foods that are native to the region we live in. For example, people in Vermont shouldn't eat oranges. While that idea may seem extreme for some, people of different ethnic backgrounds may indeed have certain specific dietary requirements. Northern Europeans need more protein, while Asians do well with more starch. Take a look at the kind of diet your ancestors had and go from there.
Antioxidants are particularly important.
But make it fun and rejuvenating, not torture. Keep trying until you find something you like to do. Do what you can, as regularly as you can. Be sure to take time off to defuse. Get enough sleep.