Inadequate nutrition for poor people is always a matter of concern, but it's interesting to see how poverty diets have evolved over time. I'm currently reading Sweetness and Power, in which a anthropologist traces the history of sugar consumption and trade. I skimmed over the complicated mechanics of sugar cane processing, but the social history aspects are pretty cool. How did sugar evolve from the luxury of kings into the obesity-causing bane of school children?
Apparently in the Middle Ages sugar was considered a spice to be liberally sprinkled over meats or mixed into wine. It was also a status-symbol. Sumptuous feasts displayed elaborate sugar figurines or models.
Everything changed with colonization and industrialization. Thanks to the Caribbean, rum and sugar were available in large quantities. At the same time, temperance advocates promoted stimulants tea, coffee, and hot chocolate as alternatives to booze.
Here's where poverty comes in. For a family struggling to put food on the table, hot tea made bread and butter feel more like a meal. It didn't hurt that sugar in the tea provided a few extra calories. I was especially intrigued by the observation that poor Englishmen eventually deserted nutritious oatmeal for bread. Once moms began working in factories outside the home, store-bought bread was a lot easier to serve than all-day-simmering porridge. Jam on bread was also a cheap, tasty, sugary alternative to butter. That's right, fast food was already an issue for busy families in the 1840's. Even then, people were relying on caffeine and sugar to get them through the day.