This uses a hacky way to prevent food from changing in sponge. This is a simple lightweight plugin as of request of https://forums.spongepowered.org/t/need-help-finding-a-good-plugin/36948/6
You can set the food value to a fixed number or link it with another value of the player such as the players health.
/ffb config value <value>
Sets the value/link of the food level for all players
Allows the use of the only command