In addition to healthy food, quantity matters as well. Find the right proportions for your yourself, and remember to eat seasonally and ethically (i.e. by supporting local producers). We were never meant to rely on foreign countries for a huge percentage of our economy. We will have 90+% reliance on internal economy in the future, and only a minority of food and other goods will be imported.
If you can, only eat organic food. When it comes animals, they should be eating their natural diet. For example, grass for cows/lambs/goats, worms/seeds for chicken (not corn). Unnatural diet damage animals making them sick and unhealthy, which in turn requires the need for antibiotics which are stored mostly in animal fat.
When cooking, it's best to use beef tallow or similar. Always avoid seed oils as they are unhealthy for eating. Extra virgin olive oil and coconut oil are best for seasoning salads and to be consumed raw in general. So, for example, if you want to season your beef meat after cooking, I'd use ev oil and oregano or mint.
Aromatic spices are good to use. They exalt the flavour of food and have good properties. Just be sure you know what you're doing instead of using pre-made mixed spice nonsense or chucking a pound of whatever in your plate like many people do nowadays. Common sense is key.