If you're talking about an online tournament, then sure as long as you can keep your attention and focus since no one would know otherwise.
If you're talking about in person, then it's probably best to stick to snacks or smaller bites as you're playing. Gauge how long you can expect to play if you were to make a long run into the tournament and see if you can eat a bigger meal beforehand to avoid eating at the table if you can't multitask efficiently.
I eat even if it's during a game. some professional player advises to eat light such as a salad. because it has certain foods that can prevent you from playing your A game. but for my part I do not follow this advice because I like to eat when I am hungry.
Obviously if you play for 5-6 hours or more you can eat something in the meantime I think.
But for sure, that’s not the time to eat half a pound of steak or eating a giant burger shouldn’t be timed for that either.
So I just wanted to aim that if one is already eating something it shouldn’t be heavy food because then the thinking will also slow down in my opinion.
So if you are already hungry man you should eat something but only light.
Well ... if we are talking about a very long tournament ... of course you have to eat .... in my personal case ... I always prepare my food before starting a long tournament ... and I take advantage of breaks 5 minutes to heat it in the microwave ...!