Is it okay to eat dark chocolate when managing my diet?

I am currently managing my diet.

I am eating very small amounts, mainly focusing on protein.

Eggs, chicken breast, cucumber, or cabbage

I'm eating like this and I'm getting on my nerves.

I keep getting annoyed.

It just so happens that it is my eldest's exam period, so I am even helping them with their studies.

I need to talk a lot, but I'm really running out of energy.

It is difficult to prepare and eat a big meal.

Among the snacks you can eat in short bursts while studying

What could there be?

I have dark chocolate at home; is this amount okay?

I'm curious~