Everyone is a little different. People have different nutritional needs. Some can eat anything and and appear not to gain weight, have greasy skin etc. Other it is the opposite. Each individual can find a nutritional balance unique to their body.
The US Government food pyramid may make it all look pretty simple. Stick to the rules and be healthy. For the most part this is true. In today's world there is the opportunity to eat better and improve overall health. Just what is best for optimum human body growth and aging continues to be a bit of a gray area.
Its generally understood that junk food does not encourage optimum health. There are mixed views for better health. Every other week it’s seems some food, herb, or drug is good for this or that. It’s hard to keep up. In general, everyone benefits from moderation, eating a diet less processed foods, light exercise (walking).
Get more nutrition from less food, you will gain from having less waste to process.
Where do you get good nutrition? Migrate from the processed food shelves to living off fresh vegetable juice, salad based meals and fresh natural food sources.