I think that it is more of a matter of demand, in some countries, than full awareness. It is funny that, in my country, the opposite is true. Healthy foods, here, are collected from plains or mountains or green areas inside villages or towns by poor men & women and they are edible herbs or grasses which are usually cooked without meat. The demand, here, is high on sausages, hot dogs, salami and the like (i.e. junk food) which are far lower in their content of nutrients. 

Cost of any product increases when the need is understood. People live for food. and food makes them live. Healthy food by definition is simply asking you to take good food. Simple food grown in your garden is good. You drink Cola and your bones become weak. So you need Calcium. Milk tates good but bland milk is not taken which is healthy. Mask it by Horlicks or bournvita or pediasure. It becomes costly. Wheat is good.  But eating wheat products require some preparation so industry comes food becomes costly. Cities are bulidings and roads and industries villages are food and agriculture. so pack and transport becomes expensive. In general the man lives away form food source and near the comfort zone. to him Food is not a priority to him comfort education and income is important.So heathy food becomes expensive.