コーヒーは１日3、4杯まで、それ以上は良くないって英語でなんて言うの？

Both of these examples are saying that drinking more than four cups of coffee a day isn't very good for your health or your body.

To say that something is not 'good for your health' is to say that it can cause damage to your body either in the short or long term.

"Coffee tastes good, but drinking a lot of it is not healthy." Tastes good - Has a good flavor. A lot - a large quantity, 3-4 cups, a pot of coffee, etc. As with anything, too much of a good thing can be unhealthy.

When giving statistics about something, it is important to be accurate. Is it 3 or 4 cups of coffee a day? Presumably your opinion is based on some research and the statistics will be available.

This is a simple way to explain to someone that it's unhealthy to consume more than three cups of coffee a day. This is applicable in all English dialects. I hope that this helps! :)

"Excessive coffee consumption can be harmful for your body" 'excessive' used to describe something that is more than necessary/lots of something. 'consumption' is a term used to describe consuming/eating/drinking something, in this case coffee. If something is 'harmful' for your body this is describing something that can cause harm/damage.

When you want to explain the dangers of drinking more than three or four cups of coffee to a person, then you may express it in the following ways: -Drinking more than three of four cups of coffee a day is not good for your health -Drinking more than three or four cups of coffee can be hazardous to your health -Drinking more than 3 or 4 cups of coffee is bad for you.