Discussing Effects - 1 - revised

     My father is an amateur of coffee.  He usually drinks two cups of coffee every day.  However, when he is busy with his work, he will drink more than three.  According to the research, people drinking a moderate amount of caffeine won’t cause any harm.  In contrast, if you ingest more than 500 to 600 mg a day (four to seven cups of coffee), there are several negative effects which harm your health.  First, drinking coffee will make you feel energetic.  But if you drink too much, you may get insomnia which keeps you from sleeping and you will feel nervous and anxious because you can’t sleep.  Second, your heart will beat fast or irregular, owing to ingesting caffeine more than people need in a day.  Third, caffeine may irritate your stomach so that you may have nausea or other gastrointestinal problems which make you uncomfortable.  Due to all of these reasons, I think drinking too much caffeine is not a good habitual behavior.  Maybe I should suggest that my father stop drinking more than three cups of coffee, or he will get a lot of harm from it.