Eat food. Not too much. Mostly plants.
It is not rocket science. Keep it real, keep it whole and keep it simple. My favorite quote from the essay follows:
“The problem with nutrient-by-nutrient nutrition science,” points out Marion Nestle, the New York University nutritionist, “is that it takes the nutrient out of the context of food, the food out of the context of diet and the diet out of the context of lifestyle."