In a nutshell, eat whole, unprocessed foods, organic grass fed meat - preferably from a farm close to you and that you can visit. Lots of organic eggs. Lots of animal fats. Fermented foods that you make at home (kefir / sauerkraut). Reduce carbs to an acceptable level for you, try and limit grains. Limit alcohol or stop altogether if you can. Cut out all refined sugar and seed oils completely.
Then there is the water that you drink . . . That’s a whole other topic . .