Even so, there are a number of foods out there that are no more difficult to prepare and eat than the staples consumed every day. 1. CeleryThe fibrous celery stalk is both rather nutrient-poor and more difficult to digest than most plants, thus granting it the distinction of requiring more calories to digest than the celery stalk itself actually contains. As such, a winning strategy for any dieter is to eat celery between meals to stave off hunger. Not only does this help to prevent impulse eating, but the celery itself also actively reduces the effective calories consumed by the dieter.