Answer:
All natural food is food that does not contain any added artificial ingredients such as preservatives, colors, conditioners or other chemicals.
But don't be fooled because they hide things from you. For example, when you buy all natural beef, you can ensure that no preservatives or chemicals were added to the beef itself, but they don't tell you that the cows' diet was based on artificially grown corn and soybeans that have been treated with a bunch of pesticides and chemical fertilizers. This is how most meats are these days, industrial and full of hidden lies. To avoid this, organic is the choice. Organic meat means that the animal was never given synthetic growth hormone, antibiotics, and that the animal's food was organic but at the same time, even if the corn is organic, cows are not meant to eat corn. So the absolute best choice for meats would be pastured- meaning that the animals were fed grass, which is what cows are meant to eat, not corn or anything else.