First, should you even feel hungry when you fast? This is actually one of the most common questions I get about intermittent fasting. And the answer is yes, hunger is completely normal. When you first start incorporating intermittent fasting into your routine, you will likely feel hungry after a few hours simply because your body is used to having constant access to food.
But don't worry, feeling hungry does not mean you are doing anything wrong or that you failed at fasting. It is actually due to decreases in glucose levels. The dip in glucose results in hunger pangs, BUT once your body gets used to intermittent fasting, glucose fluctuations will not affect you as much. Translation: You won't feel hungry every time you fast. Once you get in a good rhythm with fasting, that I-have-to-eat-right-now feeling will likely subside.
Most of us living on the Western diet—even a healthy Western diet—are used to glucose spikes and falls. The falls are what usually prompt us to eat. When you start intermittent fasting, you have to learn to differentiate this from true hunger.
My advice: Start decreasing overall sugar in your diet two to three weeks before you start incorporating intermittent fasting into your routine. This will help stabilize glucose fluctuations, so you don't feel those intense cravings.