Avoid fad diets-they are often incredibly unhealthy. To get all the nutrition the human body needs, you must eat a balanced diet including dairy, grains, protein, fruits and veggies, as well as fat (yes, even fat!).[8] By doing so, you'll have a healthy heart, healthy brain, and a fully functional immune system. Eating highly varied foods will also help insure you get all the vitamins, minerals, oils, and enzymes your body craves.