My opinion:
Electrolyte drinks aren't food, but just water and minerals. Amino acids/proteins would fall into food category, like broth. Juices are considered like water (if only juice and not having pulp). Energy drinks are like coffee; not foods but drinks.
I think it was St Thomas who said the rule of thumb is: "In the common estimation of men, is what you're eating considered a "food"?" Coffee isn't a food. Juice isn't a food. Vitamins/minerals aren't a food.
Coffee with butter = food. Juice with pulp = food. Any type of protein = food.
I wouldn't consider dissolved amino acids/protein to be food, similar to how sugary drinks are not food despite having carbs from the sugar. If it was a thick protein shake yes, but protein water no.
I don't think the common opinion would call my case food. Most people even consider whey protein shakes to be a drink and that's much more thick and filling than amino acids even though both are protein.