Don't eat too much, you won't be able to eat dinner!
Don't eat before dinner!
"Don't~" (してはいけません）という命令形の表現ですね。
ちょっときつい感じもしますけど、子供に対してはよく使うお母さんも多いのでは？？
"Don't eat too much" (そんなに食べ過ぎてはいけません！）
"Don't eat before dinner" （夕食の前に食べてはいけません！）
"You won't be able to eat dinner!" （晩ご飯食べられないよ！）
と言う感じになります。
If you eat to many snacks now, you won't be hungry for dinner.
If you eat a snack now, you won't feel like eating dinner.
If you eat a lot of snacks now, you won't be hungry for dinner.
If you eat a snack now, you won't feel like eating dinner.
These sentences are showing the consequence or the result of eating snacks now. The result is that you will not be hungry or feel like eating later.
A lot - a big amount. For example 5 cookies, 2 apples, etc. That would be a lot to eat for a snack.
Won't - Will not - You will not feel like doing something.
Hungry - feeling like you want to eat.
If you eat a lot of snacks now, you won't be hungry for dinner.（今お菓子をたくさん食べると、夕ご飯が食べられなくなるよ）
If you eat a snack now, you won't feel like eating dinner.（今お菓子を食べると、夕ご飯が食べられなくなるよ）
これらの文では、今お菓子を食べるとどういう結果になるのかを表しています。
A lot - 量が多い。例えば、クッキー5枚、リンゴ2個など。これはおやつとしては量が多いです。
Won't - Will not の短縮形。"You will not feel like doing something"
Hungry - 空腹の／お腹がすいた
If you eat too many snacks you will not want your dinner
When talking to a child it is always best to explain something in a simple way so they will understand so to tell them to watch what their eating then you would say 'you won't be able to eat all your dinner' another way to say this is 'if you eat too many snacks you will not want/eat your dinner'
子どもに説明するときは、分かるようにシンプルな言い方をした方がいいです。ですから、食べ過ぎないように注意したいなら、'you won't be able to eat all your dinner'（夕ご飯食べられなくなるよ）と言えます。
他に、'if you eat too many snacks you will not want/eat your dinner'（お菓子食べ過ぎると、夕ご飯食べられなくなるよ）と言うこともできます。
Be careful not to eat too much or you will spoil your appetite.
You won't want to eat your dinner if you eat too much.
The first sentence uses the word 'appetite' which means the desire you have to eat and enjoy food. You are warning the child that they will ruin their enjoyment of the meal if they over eat now.
The second sentences is a simpler way of saying the same thing. It shows they will have no desire to eat.
Stop eating that else you won't have room in your stomach for dinner.
Don't eat too much of that else you won't be able to eat dinner.
You'll spoil your appetite for dinner, stop eating that.
Use the above sentences to explain that snacks shouldn't be ingested before dinner else there will be little appetite for dinner.
Spoil: ruin
Ingest: consume, eat, swallow
Appetite: the desire to eat
Our parents always told us this, we need to leave room for dinner so that means not eating anything when it comes close to dinner.
A very light snack can be consumed if the child is very hungry while waiting for dinner to be ready.
The sentence "(won't have room) in your stomach" means that there will not be any space in the stomach to fit in more food.
これらの例は、夕食の前におやつを食べると、夕食が食べられなくなることを表しています。
Spoil: だめにする
Ingest: 食べる、飲み込むこと
Appetite: 食欲
私たちの親はいつもこういいますよね。夕食のためにスペースを残しておかないと、夕食が近くなると何も食べられなくなってしまいますから。
もし夕食の準備の間に子供がどうしてもお腹が減っているなら、軽めのおやつを食べるといいでしょう。
"(won't have room) in your stomach"とは、他の食べ物が入るスペースがお腹にないことを意味します。
Don't eat the snacks or you will spoil your dinner.
You need to eat good food at dinner not snacks beforehand.
If you eat snacks you will spoil your dinner.
Don't eat the snacks or you will spoil your dinner.
You need to eat good food at dinner not snacks beforehand.
No more snack because it 's too close to dinnertime.
Dinner is more healthier for you than snacks.
I need you to wait and eat dinner instead of snacking.
If you eat snacks you will spoil your dinner.
（おやつを食べると、夕飯が食べられなくなるよ。）
Don't eat the snacks or you will spoil your dinner.
（おやつを食べないで、そうしないと夕飯が食べられなくなるよ。）
You need to eat good food at dinner not snacks beforehand.
（先におやつじゃなくて、栄養のある夕飯を食べないと。）
No more snack because it 's too close to dinnertime.
（夕飯の時間がすぐだから、もうおやつはおわり。）
Dinner is more healthier for you than snacks.
（夕飯はおやつよりもヘルシーだよ。）
I need you to wait and eat dinner instead of snacking.
（おやつじゃなくて、夕飯を食べるまで待ってて。）
"Don't fill yourself up"
This expression is used when speaking to someone who is eating a lot of food and you do not want them to get 'Full', 'Full' is when you cannot eat anymore food.
"You won't be able to eat your dinner"
A simple and casual sentence explaining that you will not be able/cannot finish your dinner/meal.
"Don't fill yourself up"（お腹いっぱいにしないでね。）
この表現は、何かを食べていて、お腹いっぱいになって欲しくないときに使うフレーズです。'Full' とはお腹いっぱいのという意味です。
"You won't be able to eat your dinner"
（夕食が食べられなくなるよ。）
これは、夕食が食べられなくなることを伝えるカジュアルなフレーズです。
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