Regen: Regen drinks, mainly juices, return hit points to the user at a slow rate. These food items tend to have a duration of 2 to 10 minutes. Regen food items do not stack with the spell regen, but they do stack with bards' Paeon (regen) songs.
Refresh: Mainly juices, refresh food items return mana points at a slow rate to their users. The effect of these drinks usually lasts from 1 to 5 minutes. Refresh food items to not stack with the spell refresh, but these food items can be used in conjunction with bards' ballad (refresh) songs.
Note: A player can simultaneously use one of each food type. However, players cannot simultaneously use more than one of the same food type.

Food Duration
The effects from various types of food can range anywhere from a couple minutes to several hours. Generally, high-quality versions of food last significantly longer than their normal-quality counterparts. Plan ahead when choosing your food items by trying to anticipate how long you'll be needing the added stat bonuses.
3 Minutes: The normal-quality versions of cookies, sweets and FFXI Gil snack foods give effects with 3-minute durations. These items stack to 99.
5 Minutes: The high-quality versions of sweets and snacks last for 5-minute durations. All effects from raw food, such as raw fish, meat and vegetables also last for 5 minutes.
30 minutes: Normal-quality foods that stack to 12 items last for 30 minutes. This category includes most of the food in Vana'diel.
60 minutes: High-quality food items which stack to 12 have durations of 1 hour. Sometimes it is most cost efficient to buy the high-quality foods, if you know you're going to be in a party that won't waste the longer-lasting food effects.
3 hours: Normal-quality, non-stackable foods last for 180 minutes, or 3 hours.
4 hours: High-quality, non-stackable foods last for 240 minutes, or 4 hours.