Rice and wheat are subsidized in India too. And unlike US poor, the poor in India can't afford to supplement it with a Big Mac, Fried Chicken or a Premium Southwest Salad.

They are skinny because they eat less. They cannot afford 2500 calories, so they consume 2000 calories (mostly rice or wheat, depending on region) and suffer adverse health as a result. They also get exercise working physical jobs rather than sitting at home and watching TV.

Of course, even if corn subsidies were unique, poverty still don't explain why the US poor waste money on 500-1000 extra calories. If they were optimizing for cost, they would eat only 2500 calories of cheap corn.

Corn subsidies in the US since more than a decade are mostly for fuel; the net effect is to make corn use for food more expensive, not less.