The phrase "chow down" is an informal way of saying "eat" or "dig in." Antonyms for this expression might include eating slowly or with refined manners, such as "savor" or "dine." Other antonyms might emphasize a reduction or limitation of food intake, such as "fast" or "abstain." Other antonyms might emphasize different types of food behavior, such as "snack" or "graze," which describe less intensive, more casual forms of consumption. Alternatively, one could use a phrase like "refrain from overindulgence" or "maintain a balanced diet" to indicate a deliberate, conscious approach to eating.