Hunger Bar Not Depleting

Created a new Survival world with Natural_Regeneration disabled, hard difficulty, and all other options at defaults. The hunger bar would not deplete with or without movement as expected; neither would the hunger bar shake as if hunger depletion was occurring. On the same world, Natural Regeneration was turned back on but noticed no difference. Difficulty was then set to normal. Hunger still would not decrease but the hunger bar would now shake as expected. No hunger effects noticed regardless of the graphical indication.