[General] excess sugar isn’t exactly sweet

[Silverobama]

Hi,

What does the bold part mean?

It’s no secret excess sugar isn’t exactly sweet where your health is concerned, but now new research indicates it may take a toll on your brain as well as your waistline.

I can't understand the sentence because I think "It's no secret that excess sugar is exactly sweet where your health is concerned", but here the author used "isn't". Can anyone help?

Thanks a lot

 

[CarloSsS]

NOT A TEACHER

Your understanding would mean the opposite of what the sentence says. It would mean that everybody know that excess sugar is good for your health.

The sentence means that excess sugar, while it may be sweet for your tongue, is not very good (sweet) for your health.