Before we get to this in detail, we must enter Nutrition 101 and talk a minute about micronutrients. They are named micro because you need them in very small quantities. And truth be told, we really don't understand exactly all of the important components of food- we only understand a few.
There are two types of micronutrients- organic (vitamins), and inorganic (minerals).
Vitamins help chemical reactions take place in the body (and do other stuff we don't really understand). Most vitamins cannot be produced by the body and must be obtained from food.
Minerals help regulate body functions (and a whole slew of other things we don't understand). There are ~17 minerals needed by the body that must be obtained from food.
There are also photochemicals and antioxidants present in whole foods that do all sorts of amazing things we don't understand completely, from repairing aging cells, to preventing cancer (or essentially regulating cell growth and reproduction).
Pretty important stuff.
Most micronutrient deficiency diseases are essentially non existent in the developed world due to fortification (adding micronutrients to most processed foods), except one- obesity.
The obesity epidemic is the manifestation of rampant, widespread malnutrition in the developed world.
Wait, what??? We are malnourished?
Remember when I talked about energy dense and nutritionally deficient foods?? These foods provide ample energy (calories) but they have little-to-no nutritional value (vitamins, minerals, photochemicals, antioxidents).
This makes your body continue to seek the nutrients it needs by making you hungry. So that although your energy needs are met, your nutrition needs are not. You will continue to seek food to meet your micronutrient needs.
Unfortunately adding back nutrients to foods that have been stripped of them (think commercial bread) is not a substitute for real food. No amount of antioxidant pills, multivitamins, or superfoods (I think turmeric is all the rage now??) can replace whole foods. Not sexy, I know. But MUCH cheaper and actually works.
If you eat a meal and you are still hungry, ask yourself why. When was the last time you had a meal consisting of whole foods? Try it, your body will thank you and you just might like it.