徹夜明けは体がだるいし食欲がないのに、食べないと体に悪いからと友達がお菓子をくれたけど、甘いものなんてもっと食べたくない！です。I don' have appetite after I stayed up all night, moreover I never feel like eating sugary food. で自然な英語でしょうか。
I don't have an appetite after staying up all night, moreover I don't feel like eating sweets, especially when I'm tired like that.
I don't feel like eating when I've been up all night, and I certainly don't want to eat anything sweet when I'm exhausted like that.
ーI don't have an appetite after staying up all night, moreover I don't feel like eating sweets, especially when I'm tired like that.
「徹夜の後は食欲がないし、その上、そんな風に疲れている時は甘いものは食べる気がしない。」
not have an appetite で「食欲がない」
sugary food でも良いですが、私なら I don't feel like eating sweets と言います。
下のようにも言えます。
ーI don't feel like eating when I've been up all night, and I certainly don't want to eat anything sweet when I'm exhausted like that.
「徹夜の後は食欲がないし、あんな風に疲れている時は甘いものなんて絶対食べたくない。」
「徹夜」は be up all night を使っても表現できます。
don't want to eat anything sweet で「甘いものを食べたくない」とも言えます。
ご参考まで！
カナダ 
