what in the actual fuck are you talking about????? long press LMB does nothing? did you rebind all your controls or something? what is going on??? none of what you say in your post is accurate, there are four ways to interact with an object in the world. left mouse button only does one thing, and that's activating the subfunction of whatever is held in your hand, and holding left mouse button does nothing as far as i know. you eat food in two ways, holding e on it when its in the world, and pressing left mouse button when its in your hand. like, your post makes so little sense I'm beginning to think you haven't even played the game.
when you're looking at an object, you have FOUR ways of interacting with it:
grabbing it: this moves it to the center of your vision and uprights the object and keeps it that way. grabbed items can be rotated with right click
using it: using it uses the item, for food, using would be eating,,,,,
pick up: puts it in your offhand. this is just an inventory action nothing more
put in inventory: puts it in your inventory
it gives you a description of what each action does when you look at an object, i dont see why you cant just read it every time.