They were already running late for a doctor’s appointment, but first the Salas family hurried into their kitchen for another breakfast paid for by the federal government. The 4-year-old grabbed a bag of cheddar-flavored potato chips and a granola bar. The 9-year-old filled a bowl with sugary cereal and then gulped down chocolate milk. Their mother, Blanca, arrived at the refrigerator and reached into the drawer where she stored the insulin needed to treat her diabetes. She filled a needle with fluid and injected it into her stomach with a practiced jab.