I doubt you'll find much that won't have some impact 
@Tony 1711 .
Not easy to do , trust me 
But ignore IF you can.
And if you can't pick something low carb 
Cheese wrapped in lettuce or slice of meat ?
I like to visualise such processes as it helps me try to understand the method & it's impact 
I see the long fast overnight as allowing everything to 'settle' inside me 
Akin to a small pond covered in algae.
I want that pond to be smooth to show me the real issues and how much algae there is 
Eating anything disturbs the clouds the clarity of the pond & eating high carb must be like a speed boat churning it up 
So it interferes with the next days reading 
(Which isn't always linear, to be clear.
I've 'got' away with a naughty snack one night, only to find my good behaviour the next evening gave me a poor morning read)
Individuals, how we respond, how we feel, all of that impact us 
My view, eat if you have to, with limits
But I've found if I don't eat I'm not so hungry ...
But if I do eat, it's like starting a machine,  as if my body wakes up and want more of whatevers available.
So it can be a nuisance to give in.
Someone on here said, "if your hungry, try drinking a glass of water 'saluting the hunger'
They called it.
And wait 
If you're still hungry 20 minutes later...eat something.
I found it worked, most times 
Good luck finding a way that works for you .