Please help yourself (to 〜）.
[ご自由に](https://eikaiwa.dmm.com/uknow/questions/64159/)召し上がってください！具体的に〜を食べてと特定したい時にはtoの後ろにそのものを置きます。
例）
Please help yourself to anything you like.
なんでも[好きなもの](https://eikaiwa.dmm.com/uknow/questions/135239/)を召し上がってください。
”Dig in!”や”Dive in!”はカジュアルな言い方で！がっつく、もりもり食べ始める、食べ物に飛びつくというようなニュアンスがでます！
例）
Here's your dinner! Dig in!
夕食できたよ！どうぞ食べて！
1. You can say this when you serve someone with any dish or beverage you have prepared yourself - especially something which is a little unusual.
2. To be made by your own fair hands = a humorous expression meaning used to say that you have made something yourself:
"Where did you get this cake?" "I made it with my own fair hands."
1. ほんのちょっと変わったものを人にだすときに特に使われる表現です。
2. To be made by your own fair hands = 何か自分で作ったときに使うユーモアのある表現です。
"Where did you get this cake?" "I made it with my own fair hands."
このケーキどこで手に入れたの？ 私の手作りなのよ～
Thesre are so many phrases that fit...depending on the context ;-D
From the simple: Enjoy...Tuck in! dive right in! Eat up!
The more sophisticated among you might prefer: "Bon Appetit"
A universally understood phrase for ...Please enjoy the food
状況によって適切なフレーズがさまざまです ;-D
シンプルな表現: Enjoy...Tuck in! dive right in! Eat up!
より洗練された表現: "Bon Appetit"
誰にでも理解されるフレーズ ...Please enjoy the food
Assuming that the person is a friend or relative you can say something more informal like:
Tuck in!
Dive in!
In a more formal situation you can say:
Please help yourself.
Please help yourself to some home made cooking.
友人や親戚などに対しては、このようなカジュアルな言い方ができます。
Tuck in!
Dive in!
フォーマルな状況だったら、
Please help yourself.
Please help yourself to some home made cooking.
と言うフレーズが良いでしょう。
Tuck in (informal)
It means to eat food heartily
Can be used when serving food to family and friends
A: This looks delicious
B: Please, tuck in
____________________________________________________________________
Enjoy the meal
This can be used in formal and informal settings
Tuck in (カジュアル)
これは思う存分食べることを意味します
家族や友人に食事を出すときに使えます
A: This looks delicious（これは美味しそう）
B: Please, tuck in（どうぞ召し上がれ）
____________________________________________________________________
Enjoy the meal
これはフォーマルな場面でもカジュアルな場面でも使えます
"Tuck in"/ "Dig in" / "Dive in". Are all ways of telling someone to start eating or start dishing up for themselves. You can also say "help yourself"
"Bon appetit" is a common word used when you start a meal. It means enjoy and start eating.
I hope you like it. It is my homemade bread.' - this is when you want the person to know that you made it yourself or if it is your own recipe.
Enjoy your meal- is the most commonly used expression.
I hope you like it. It is my homemade bread.' - 自分で作ったことを伝えたい時、またはオリジナルレシピの場合に使います。
「Enjoy your meal」、最も一般的な言い方です
日本 
アメリカ合衆国 
イギリス 
南アフリカ 
アイルランド 
