No matter how healthy it is, overeating is bad for you
even if something is good for you, eating too much of it is bad
moderation in everything is important
「いくら良い物でも」= even if something is good for you.../ No matter how healthy it is...
「食べ過ぎは良くない」= overeating is bad for you / eating too much of it is bad for you
簡単にいうと、「moderation in all things is important」
「moderation」= 「節度」
「良いからといって必要以上にやったり、食べたりする」= Just because something is good (for you), it doesn't mean that you should do it (eat it) to excess
1)「何でも多すぎはよくない」「何でも多すぎると身体に害だ」と言う意味です。
Don't over-do it=やり過ぎるなよ、やDon't over-eat=食べ過ぎるなよ、と言った表現も使います。
Vegetables are good for you, but if you eat too much of it, you'll miss out on nutrients that you can't get from them=野菜は身体にいいけど、食べ過ぎちゃうと野菜では採れない栄養が足りなくなる。