If this is your first time fasting, it's a good idea to do some research so you'll know what to expect. Knowing you aren't the first person to experience a certain side effect might help you endure when all you really want to do is have a slice of pizza. Here are a few effects you can expect:  Expect to feel cranky. Cutting out sugar and other foods on which your body is dependent is going to cause withdrawal symptoms, and irritability is a major one. Expect to feel a little sick at first. You might have a headache or feel weak for the first few days. Expect to get used to the hunger. You'll definitely have some hunger pangs, but many people report that these tend to go away after a few days. Expect to feel lighter. After a few days of fasting, you should feel a mood boost and feel lighter on your feet. Having a plan in place for when cravings kick in can help keep you from indulging mid-fast. Here are a few things you can try to distract yourself from your lust for cheese and crackers:  Drink a big glass of water. Go for a walk. Getting some fresh air can help. Read a book or watch a movie that doesn't contain lengthy descriptions of meals. If you start to feel dizzy, weak, and fatigued, your fast might be doing more harm than good. Stop fasting immediately if bad symptoms persist. Be sure to see your doctor if eating normally again doesn't restore you to good health.

How would you rephrase that briefly using Chinese?
想想你禁食时会有什么样的感觉。 为战胜欲望做一个计划。 时间不要太长。