We tend to think of antibiotics as a method humans use to fight diseases. But,as The Guardian reports,80 percent of the antibiotics sold in the United States are used in animals, not in humans.
And those drugs are not used to treat illness, but rather to make animals used as food to put on weight more quickly. And a majority of those weight-increasing drugs are also used to fight human disease. That means eating animals that have been given antibiotics undermines the usefulness of antibiotics to battle illness.
Because of the prevalence of antibiotics in our food, disease organisms have developed defenses against the drugs. Currently, bacteria that have grown resistant to antibiotics lead to 23,000 yearly deaths in the United States. In her book Big Chicken, Maryn McKenna estimates that by 2050, antibiotic resistance will be responsible for an incredible 10 million deaths per year