What are some good foods that helps maintain a healthy lifestyle?

Variety. Fresh fruits and vegetables and whole grains. Some nuts and low fat dairy. Beans are a good protein source.
Healthy choices. Eat healthfully w at least 5 servings of vegetables & 4 of fruit /day (organic is best). Increase nutritional fiber. Avoid refined sugar & junk carbohydrates. Avoid sweetened juices, soda & caffeinated beverages. Watch portion sizes. No tobacco, illicit drugs & low to no alcohol use. Aim for 7.5 to 8 hrs sleep /night. Hydrate w at least 64 oz of water / day.