I think it depends on the amount of lemon juice. It is believed that lemon has more sugar than strawberry I am not a biochemist but in my opinion opinion five or more grams of carbs can break fast. I used to take lemon water years ago which caused me teeth problems. Besides acidity of lemon prepares the stomoach to digest so might create hunger. It might be great 20 minutes before main meals to improve digestion. I didn't need lemon and don't take it anymore. Pure water is wonderful.