If eaten alone, the dish effects and their duration are dependent on cooking rank.
If eaten as part of a Picnic from the Festival Food skill, the effects of foods are stacked with up to 10 dishes at once at r1 (making them much more effective) and (presumably) the duration is dependent on the rank of Festival Food of the consumer rather than the rank of the chef who prepared the food that prepared the Picnic. This skill has yet to be implemented in NA, and is part of Project Dream.
Other things to mention: The use of food buffs will be best used with Festival Food skill Picnics/Baskets, and at r1 you can stack the effects of 10 dishes for a buff duration of 20 minutes. Because of the time invested in preparing a Picnic, it would be impractical for most players to use picnics constantly. The stats from most foods will likely make little difference to players with more than 1k levels and/or nearly capped stats, but the Picnics may prove useful for situations like increasing lucky gathers, boss rooms, MA tourneys, etc. that are not expected to last a long time.
The guide will be edited once Project Dream is released, to allow for screenshots, examples, etc.
The stats, ingredients needed, etc. are captured in screenshots from the wiki. Foods are separated into categories of skillsets they would be most useful for. Some foods repeat in several categories. I have noted the costs of ingredients that can be purchased, whether ingredients can be purchased or must be gathered, and if the food requires more than one step to make.
[SPOILER="Melee: Warriors load up on hard beverages to become stronger, if a little duller, but get lucky (figures)"]
Several beverages are listed, and there are a few more on the wiki. Since most of them reduce DEX/INT to some degree, you can choose which is the best for you based on how important those stats are to you.
[SPOILER="Beverages, generally +STR and LUCK but -DEX and INT, varying degrees"]There are a few dishes I included that provide may less strength but nearly no negatives.
[Image: https://scontent-b-sjc.xx.fbcdn.net/hphotos-frc1/t1/1476149_10203263049761675_763559_n.jpg]
Ingredient cost: 1140g
1 step
Can be purchased at 3 star quality
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn1/t1/1601345_10203263049641672_1880181024_n.jpg]
Ingredient cost: 4220g
1 step
Can be purchased at 3 star quality
[Image: https://scontent-b-sjc.xx.fbcdn.net/hphotos-ash4/t1/1654016_10203263049721674_2119460616_n.jpg]
Ingredient cost: 2760g
1 step
Can be purchased at 3 star quality
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-ash3/t1/1560668_10203263049801676_1631895502_n.jpg]
Ingredient price: 2785g
1 step
Can be purchased at 3 star quality
[/SPOILER]
My top picks: No cons, still decent STR. Onion Rings would be good for Melee Fighter hybrids and Hot Chocolate would be good for Gunners or Spellswords. Steamed corn has decent strength and very good HP, with OK levels of others stats.
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc3/t1/1911899_10203263049681673_1270247291_n.jpg]
Ingredient cost: 35g, 1 water and 1 egg must be gathered
2 step
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn2/t1/1896809_10203263049841677_1722618512_n.jpg]
Ingredient cost: 570g
1 step (alternatively you can make it a 2 step dish and make the steamed milk yourself)
Can be purchased at 3 star quality
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn2/t1/1656146_10203263191565220_340413965_n.jpg]
Both ingredients must be gathered
1 step
[/SPOILER]
[SPOILER="Magic: Radagast the Brown ate mushrooms, you should too!"]
Only a couple of easier options here, most of the most potent +INT/+MP dishes involve seafood.
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc1/t1/1797573_10203250728653655_138253630_n.jpg]
Ingredient cost: 495g, the mushroom must be gathered
1 step
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn2/t1/1896809_10203263049841677_1722618512_n.jpg]
Ingredient cost: 570g
1 step (alternatively you can make it a 2 step dish and make the steamed milk yourself)
Can be purchased at 3 star quality
[/SPOILER]
[SPOILER="Martial Arts: Onion rings make as much sense as wax on, wax off, but just try it."]
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc3/t1/1911899_10203263049681673_1270247291_n.jpg]
Ingredient cost: 35g, 1 water and 1 egg must be gathered
2 step
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc1/t1/1897798_10203263156124334_1611695812_n.jpg]
Ingredient cost: 3450g
1 step
[/SPOILER]
[SPOILER="Archery: An entire meal you can hold in one hand, though you should still have two on the bow"]
There's really nothing (outside of gacha/event food) better I've seen for DEX on the wiki, and it's really easy to make. The only thing that doesn't make any sense is why it's a baked food.
[Image: https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-frc1/t1/1907583_10203242010515707_1905090786_n.jpg]
Ingredient cost: 1539g
1 step
[/SPOILER]
[SPOILER="Alchemy/Defense: Nothing wrong with being able to take a few more punches"]
There are one or two other +MP/SP/HP dishes, but I believe this is the strongest, and you can bake it with a very lenient 3-5 star quality for the same buff potency.
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc3/t1/1610026_10203263173124759_65331378_n.jpg]
Ingredient cost: 1235g, but the mana herb must be gathered
1 step
[/SPOILER]
[SPOILER="Hybrid: For the Renaissance Man"]
Note: It is possible that the best way to build a hybrid Picnic using Festival Food would be to use stronger, single stat dishes that have 1-2 stats than to use multiples of these more generic buffing foods. Each of these has some of my comments on them.
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn2/t1/1656146_10203263191565220_340413965_n.jpg]
Both ingredients must be gathered
1 step
Useful to melee leaning (or melee lacking) hybrids or fire alchemists.
[Image: https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-prn2/t1/1662215_10203263191685223_1739690226_n.jpg]
Ingredient cost: 9630g the fish can be optionally gathered
1 step
Moderate boosts to anyone but an alchemist.
Can be purchased at 3 star quality
[Image: https://scontent-b-sjc.xx.fbcdn.net/hphotos-ash3/t1/1560497_10203263191645222_140919373_n.jpg]
Ingredient cost: 6210g, water must be gathered, fish can be optionally gathered
1 step
Marginally more potent in certain areas than the previous dish.
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn2/t1/1896809_10203263049841677_1722618512_n.jpg]
Ingredient cost: 570g
1 step (alternatively you can make it a 2 step dish and make the steamed milk yourself)
Can be purchased at 3 star quality
A good choice for gunners
[Image: https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-frc1/t1/1907583_10203242010515707_1905090786_n.jpg]
Ingredient cost: 1539g
1 step
I don't think any of the melee dishes had more than 20 STR as well as not decreasing DEX, so this is probably one of the best choices for puppeteers.
[Image: https://scontent-a-sjc.xx.fbcdn.net/hphotos-frc3/t1/1911899_10203263049681673_1270247291_n.jpg]
Ingredient cost: 35g, 1 water and 1 egg must be gathered
2 step
Probably a favorite of melee-fighter hybrids, without any cons.
[/SPOILER]
[SPOILER="Life:"]
For lucky gathering bonuses, mostly.
[Image: https://scontent-b-sjc.xx.fbcdn.net/hphotos-frc1/t1/1795676_10203242009075671_1729807228_n.jpg]
All ingredients must be gathered
2 step
Can be purchased from an NPC for the 3 star quality, which is notably only a couple points less potent than 4/5 stars.
[/SPOILER]
Specials thanks to Azareel and Kingofrunes for particularly useful information prior to this post's revision.
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