I think the key to eating healthy, is to eat as close to natural foods as possible. Preservatives and additives(all that stuff you can’t pronounce on the back of packages), are terrible for you.
Also, sugar is your enemy, especially added sugars. That stuff makes foods taste good, but it is poison for your body. I cut out a lot of sugar a few months ago. I quit drinking soda, cut out a lot of sugary snacks, and also quit drinking Gatorade(that stuffs not so great for you either). I have a really hot job, where I sweat a lot, it’s 125F+. I used to drink a Gatorade with my lunch, to rehydrate. Now I drink water and eat fruit, and feel so much better. I also started drinking a lot of Milk.
There’s also a lot of misleading information on packaging of foods too, a lot of foods that say they are healthy, really aren’t. There’s multiple websites where you can look up how healthy and certain brand name of food is(bread or cereal for example). There’s some brands of wheat bread, that is actually worse than white bread. Same with yogurt, some yogurts have a ton of added sugar. Make sure you do your research, and don’t just “think” your eating healthy, know what you are putting in your body.