We all know we should be thankful for the food on our tables — but why? Here are 14 eye-opening facts about nutrition, farming, and crop varieties around the world that help answer this question.    1. Poor people in developing countries often spend 60-80% of their income on food. Americans spend less than 10%. Ayme family, Ecuador. Photo credit: Peter Menzel and Faith D’Aluisio. 2. 75% of the world’s food is generated from only 12 plants and 5 animal species. Kale is probably not...