$10 a day is $300 a month, which is a lot to someone near the poverty line (~$1000 a month). The maximum SNAP (food stamps) benefits for an individual is $194. I know SNAP is supposed to be supplemental, etc., but the government has decided someone who is very poor shouldn't have access to the level of nutrition you're talking about.

You can eat on $200 a month without much problem. I received max SNAP benefits for several months and I spent about $120 a month on food, so I had money left over at the end (being a vegetarian helps).

This really isn't relevant to the point at hand (or maybe it is, who knows?) but I think poor people would have an easier time if the means testing for food stamps were looser. The benefits fall off steeply. If someone is making a thousand dollars a months and working full-time or close to it, the government can chip in more than $10-20 to give them access to healthier food.