Without plant breeding and domestication, would most of the foods consumed by humans evolve to become inedible?
Plant defense against herbivory

Plenty of plant species evolved defense mechanisms. There is a large variety of defense mechanism. Have a look at the wikipedia article Plant defense against herbivory for more information. Such defense mechanism often comes at a cost and therefore the mechanism can be maintained only if herbivory is sufficiently common and costly. Note that herbivory might be beneficial to some animal species typically as it can help to disperse the seeds. 

plant-herbivores Co-evolution

Herbivores co-evolve with plants and develop mechanism to deal with plant defense mechanism. Such coevolution often yield herbivores to specialize in feeding in a handful of plant species only.

Human consumption

Most of what human consume is artificially selection. We specifically allow the breeding of individuals that present trait that are pleasant to us. In such condition, a defense mechanism would be a highly deleterious trait.


  Do species evolve to avoid being consumed, especially the animal species which have no need to leave seeds?


I don't understand this sentence. Do you mean "[..] especially plant species being consumed by animal species that don't help spreading the seeds"?

If this is what you meant, then yes. If herbivory comes at non benefit for the plant, the overall cost of herbivory will be more important for the plant. All else being equal, a mutant that present a defense mechanism would have a higher fitness if the herbivores do not offer any benefit to the plant being eaten.