See this article in Foreign Policy which argues that the poor are probably less hungry than we think. The authors say:
In Udaipur, India, for example, we find that the typical poor household could spend up to 30 percent more on food, if it completely cut expenditures on alcohol, tobacco, and festivals. The poor seem to have many choices, and they don't choose to spend as much as they can on food.
Studies have shown that when very poor people get a chance to spend a little bit more on food, they don't put everything into getting more calories. Instead, they buy better-tasting, more expensive calories.Read this article and learn why, when food prices drop, poor people eat less. It turns out the very poor are not so different from the rest of us.