The courts have ruled that putting a prisoner on short rations (the old "bread and water" punishment) is "cruel and unusual" punishment.
Likewise, since it is no loger cruel, animal shelters can save a lot of money putting dogs and cats down. No more drugs are needed. They can just let them starve to death if they are not adopted.
Better yet, take them all out in the middle of the desert, drop them off and let them die of thirst.
Make sure they have umbrellas to keep the midday sun off of them and beds to sleep in. So humane!