Currently in Vanilla holding anything in your offhand slot increases your hungerrate by 20% (VS Wiki) and I felt this debuff was too strong, especially to people who like to always be holding a light source. This mod adds a different hunger rate increase depending on the item in your offhand slot and also new different penalties.

Smaller items like the basic torch and the ink and quill  - 5% hunger increase

Shields - 15% hunger increase

Anything else (lanterns hammers tongs etc.) - 10% hunger increase

In balance to this buff to the hunger rates, now when you have an item in your offhand you get -10% to your animal harvesting speed and block breaking speed regardless of item.

This mod is heavily based on previous mods changing the offhand penalty, this mod is an alternative balance to them, check them out here: https://mods.vintagestory.at/offhanddebuffpatch https://mods.vintagestory.at/show/mod/8034 https://mods.vintagestory.at/show/mod/276  

To Do:

Currently if you're holding something in your right hand there are no debuffs so by my logic there should be no debuff if you're only holding something in one hand regardless if it's a in a normal slot or the offhand slot. So I'd only want the debuffs to happen if you're holding something in both hands at the same time.