You can get hungry, thirsty, tired, hot and cold. You will see think-bubbles above your character to indicate their needs. If you are hungry, thirsty, cold or exhaust yourself, you get tired faster. You can consume things manually by dragging them to the respective slot in your inventory (B). Prepared snacks are more efficient than eating ingredients.
You can also stay fed while offline, see Offline Play & Crafting
You regenerate health slower depending on how hungry you are. You have to eat to stay fed. Your character will only eat when hungry, so you can not waste any food by trying to eat.
You regenerate stamina slower depending on how thirsty you are. You have to consume berries, tomatoes, snacks, meals or drinks to not get thirsty. Alternatively you can press the gather key (R or MMB) with your mouse over water to drink from there directly. You can not drink (green) swamp water or ocean water at the coast.
Tiredness / Sleep
You get tired by regenerating health and stamina and by doing stuff in general. When you are tired you have to sleep. When your char is very tired it will sit and start to sleep. If you wake him up with a movement command he gets a short speed debuff. If someone wakes him up, he won't get the debuff, so if enemies approach you can wake your friends up by pushing them. If your char gets extremely tired he'll get drowsy and will become difficult to steer. When tired you are slow and vulnerable to attacks and escaping enemies becomes difficult.
When it’s too hot you get thirsty faster. When it’s too cold you get hungry faster. Extreme cold can even cause you damage (though it will not kill you).
You can stand in water to cool down. You have to get warmer clothes, go indoors or stand near a fire to avoid cold, especially in winter, at night and with storm and rain. Being wet also cools you down.
While you are stunned you can not do anything.
Every item in Blossom & Decay has a weight and there is only a limited amount of weight a character can carry without being overloaded. Currently a character becomes overloaded when the carried weight exceeds 200 units. This results in slowdown paired with a steady loss of stamina while moving and therefore is a potentially dangerous condition. Read about the Weight Load Mechanics