This is coming from the veinminer plugin (it's in the config.yml), so very easy to do. This is where it's coming from in the default config
[CODE]Hunger: # Various hunger-related options
HungerModifier: 4.0 # How much exhaustion is applied for every block broken while vein mining. Every point is 0.025 hunger/exhaustion per block
MinimumFoodLevel: 1 # The minimum food level required to vein mine. If vein mining while this value is hit, it will stop
HungryMessage: "&7You are too hungry to vein mine!" # The message to send the player when they are too hungry[/CODE]