In this dialogue, the purpose of philosophy is to attain happy, tranquil life, which can be described by ataraxia-peace and freedom from fear.  By living with friends in a self-sufficient manner.  Epicurus teaches us to live without fear of reward or punishment from the gods:  death is the end of the body and soul and therefore should not be feared. And that events in the world are ultimately based on the motions and interactions of atoms moving in empty space.  These two great philosophers attempt to explore the way we feel pleasure and pain.

Epicurus:  The pleasure of foods in life are regulated by the pleasure and pain receptors in the body, but when we manipulate or process food, we no longer have a way to keep a balance.

Plato:  So this is why people become over-weight, have heart attacks and get sick?

E:  Yes, Take a glass of wine, it has very few calories, but it has more sugar and alcohol per volume than a large sack of grapes.  Or to put it another way, press the sack of grapes and process a cup of wine.  Drink this glass of wine and the pleasure center in the brain gives the body pleasure.

P:  It tricks the pleasure center because it concentrates the sugar and alcohol in the fermented juice by removing all the pulp and skin of the grape.

E:  Yes, we loose all the nutrients from the grape while retaining the alcohol and sugar in the fermented juice.

P:  And we get sick, if we drink too much wine.

E:  Yes, and what is worse, we feel like we only want wine because our brain feels pleasure.

P:  We would rather drink wine than water, even if it makes us sick.

E:  Yes, our ability to regulate the use and nutrients our body needs is lost due to the way we process foods.

P:  There must be a way to restore balance.

E:  Yes, it helps to talk about it and find ways to change back to eating food (grapes) that supplies us with what our body needs to grow and work in a better way.

P:  Sounds like a good subject to study.

E:  Yes, at least until we start eating in a more regulated manner.