Whole foods are obtained directly from plants and animals as opposed to processed foods, which are stripped of their natural nutrients and have artificial ingredients added.  Whole foods are profuse with micronutrient vitamins, minerals, antioxidants and phytochemicals. 

Processed foods have a longer shelf life than whole foods because artificial ingredients are added to them, so that these foods can have a  longer shelf life.  Monosodium glutamate is also added to make it taste better.  Unlike processed foods whole foods have nothing added or taken away as they are obtained directly from nature.

An example of a whole food is brown rice.  In the production of white rice the germ and inner husk is removed resulting in the loss of vitamins and minerals such as vitamin E, selenium, iron, magnesium, zinc, B vitamins, lignans, phenolic acids, phytoestroges and other phtyochemicals, that are considered helpful in reducing the risk of heart disease, cancer and diabetes.  All of these nutrients are also essential to build muscle. 

Many people prefer processed foods because it is easier to prepare, more convenient and supposedly tastes better.  In supermarkets processed foods are also better promoted than whole foods by being positioned in the most conspicuos places. 

You should aim to incorporate as much whole foods as possible in your diet to build muscle.  Whole foods release energy slowly in contrast to processed foods, which give you a quick burst of energy then a crash.  Thus, if you want to last through your workouts opt for whole foods instead of processed foods.