Eatable and edible are both adjectives that describe the condition of food. A food that is edible is something that is not poisonous and will not harm your body should you eat it. A food that is eatable is something that is edible as well as delicious.
Eatable refers to the taste of the food, where as edible distinguishes it as a food fit to be consumed.
In dire situations, humans will look for edible foods, even if they may not be eatable. An easy way to make the distinction would be to take the example of raw foods, like raw chicken, or uncooked rice, which are edible, but not eatable until cooked.
The etymology of the words also gives us insight into this subtle difference in meaning. Eatable is a word that combines two other English words- eat and able. Hence a food we are able (and willing) to eat. The root of the word edible lies in the Latin word edibilis- it’s the verb describing the action of eating, in subtext, a food that can eaten without harming the individual eating it.
Thereby, an eatable food is always edible; however an edible food is not always eatable.
Today, the word eatable is used rarely, seen as informal, and often used to describe a sub-set of food as opposed to the condition of foods, for example, finger foods at a party are often called eatables. Edible is more colloquially used and replaces eatable, often in the negative sense. The common phrase “it’s barely edible” is used today not to describe food unfit for consumption, but food that is not pleasant tasting.
Despite the change in meaning in informal gatherings, there still remains a key difference between eatable and edible that is important to remember for proper English use.