Eat healthy. Seems simple enough, until you actually start doing it. What foods do you buy? How do you track calories? How much of what do you really need? What should you avoid? Many of us do not have the time, or energy, to follow a calorie chart.
Men's Health have posted a video that simplifys it all for us:
While it's true that a multivitamin is optional, it is highly recommended that you take one. Why? Well, because of our declining food quality. Over-farming, pesticides, storage, months of refrigeration, genetic modification... all these, and more, contribute toward poor quality of the food we eat today.