Not eating in Grim Soul is arguably more dangerous than dealing with the monsters. This includes making sure you have water also. After a certain period of time, your character will indicate that he/she is hungry or thirsty. You will need to hurry and come up with some consumables.
If you don't, then your health will start to drain. It depletes at a fair rate too, so you'll need to think fast. Fortunately, you should be able to find several bushes with berries on them. Grab the bushes and take the berries, then munch away.
Water is a bit more scarce. Check any chests, dead animals, and other things for a shot at some water. The good thing is that when you find some, you're normally given multiple bottles of them. It's always good to know that you have a couple of extras leftover when you need it.
Manage your inventory
This is highly critical to your overall survival. We talked about how food was arguably the most important thing in the game earlier. Well, you won't be able to carry food if your inventory is full. And early on, you won't have much space to work with.
So, try and look over the items you have right now and read the descriptions to see what they do. If you feel that you don't need it, then remove it. This will free up a spot for food or water. So when you eventually start going hungry, then you'll be ready.
If you are hungry and your inventory is full as you find some food, you can eat the food right then and there which is helpful. You don't need to have it in your inventory to eat. But, if you want to save some for later, then yes, you need it in your bag.
Practice your craft(ing)
In a world as dangerous as Grim Soul Survival, it's always good to try and make yourself feel as comfortable as possible. Create things like weapons and even houses and furniture. It's important that you start by creating a couple of essential items.
One is an ax, and the other being a pickaxe (lots of axes I know). The ax will allow you to chop down trees and gather wood. Meanwhile, the pickaxe will enable you to gather stones that can also be used in crafting. Both of these are pretty easy to create.
And if you started with the 20 logs starting gift, then you'll be well ahead of the game. You just need two limestones to create the items. Now that you have them created, you can gather a ton of good materials to help you craft a cozy home or some apparel among other things.