Give me a grilled mouse on toast, any day bruv ! 😹👍
Whats the best chess snack???

Pawns.
Yum, yum, yum!
lol, clever blueemu.
Obviously depends on if online, OTB casual, OTB Tournament etc. but usually a granola bar. Perhaps a cup of coffee - pretty much anything that is easy to clean-up and not too difficult to carry. Favorite meal is a whole different story

A bag of potato chips. The real crunchy ones. Just to mess with my opponent
The only think you are messing with a bag of crunchy potato chips is your health. Your opponent couldn't care less even if you have a gun on your head.
By the way , he is talking for on line chess , eating is not allowed in OTB.
Where does it say he's talking online chess?

i like bringing (quiet-to-eat) fruit like bananas or oranges to eat during games, and usually make some sort of bean or lentil salad to eat between rounds. i try to eat at least a little bit after every game, rather than having big meals and then feeling tired. i also try to avoid eating junk food during tournaments, which can be hard because there is lots of cheap pizza near where i play. in high school i would eat like crap during tournaments (taco bell, burgers, you name it) and always start running out of steam by the end of the day.

A bag of potato chips. The real crunchy ones. Just to mess with my opponent
The only think you are messing with a bag of crunchy potato chips is your health. Your opponent couldn't care less even if you have a gun on your head.
By the way , he is talking for on line chess , eating is not allowed in OTB.
Where does it say he's talking online chess?
Already explained that eating is not allowed in OTB genious.
That is not an answer to my question.

USCF allows snacks during OTB tournaments, as long as they don't make distracting noises.
You can eat while playing? That is very surprising.
I am still waiting on an answer.

Cheese and chocolate give a false sense of security to your brain, they also comfort you. So those are probably not that good when you have got an open position and got tactics tying down tactics. Also Bananas, apples and for the junky person, Spicy chips/cheez-its. Bananas are the best, they have potassium and other nutrients to help you in a game, also apples for obvious reasons and spicy things do tend to keep your brain ticking (as long as you keep on eating them, stopping can make get tired). Out of all the things I said, Pop/Sugary drinks are the worst, firstly they are really unhealthy, most importantly the extra sugar makes your insulin rise a lot causing you sugar levels to immediately crash (making you sleepy). Then it takes about 3 hours for you sugar levels to neutralize.
I personally prefer to put goldfish or granola in cups but I'm eating off brand yogurt raisins. What do you use?