Currently, there are config options to make using a wand cost XP, but no corresponding options to make using a wand cost hunger.

To rectify this, I would like to propose the following config option: blocks_per_hunger
When this is set to a value greater than 0.0, it costs 1 food point to place X blocks with a wand, where X is the value of the new option.

The hunger cost is implemented by adding the appropriate amount of exhaustion to the player for each block placed, where 4 exhaustion = 1 food point (exhaustion per block = 4 / blocks_per_hunger).

For example, when blocks_per_hunger is 32 and a player is placing 48 blocks in a single action, each block placed will add 4/32 = 0.125 exhaustion for a total of 6 exhaustion or 1.5 food points.
Similarly, using a diamond wand to place a full 64 blocks while blocks_per_hunger is 800 will add 4/800 = 0.005 exhaustion per block for a total of 0.32 exhaustion.
If a player's hunger level reaches 0 during a wand action, the action aborts with a "not enough hunger" message.

I'll add this, thanks for the suggestion. It should be relatively simple to implement.