One approach is simply to occasionally skip a meal or a day's meals in a fairly random pattern. That would, presumably, mimic what might happen "in the wild".
Robb Wolf recommends people to first cut down carbohydrate consumption and ramp up sleep (in as dark a room as you can make it) before trying fasting. He reckons you must get those two things right first. He's said this on his podcast and repeats it here:
Sleep+Intermittent Fasting | Robb Wolf | The Paleo Solution book and podcast | Paleo diet, Paleolithic nutrition, intermittent fasting, and fitnessA great question is “how do I implement intermittent fasting?” to which I would respond: Implement it to the degree it makes you feel better and improves your life. Two things you MUST do: remove refined carbs from your diet AND get adequate sleep.