A simple formula for health, as much as there is one, comes from Dr. Fuhrman: Health equals nutrients divided by calories (H = N/C). In other words, the more micronutrients you can get in the fewest number of calories, while still eating whole foods, the healthier you’ll be. (Of course, the assumption here is that the total number of calories is within a reasonable range—enough to thrive but not more than you need to support your metabolism and activity level.)
Notice that there’s no explicit exclusion of animal products there, by the way. But because “whole” animal products are calorically dense and relatively low in micro nutrients, they typically score pitifully low on the H = N/C scale compared to plants.