Well…It depends on your BMI. If you are an average and healthy person you can take about one-half of the lemon squeezed into one glass of water, twice daily. But if you are overweight, you can drink the lemon water made by one whole lemon in a glass of water, twice daily. It is the presence of 5% citric acid that gives a tarty taste to lemon. It is better to avoid sugar while taking lemon water in order to avoid excess calories. Lemon water if taken daily can help to promote a healthy digestive tract and the problems like constipation, indigestion and hiccups can be avoided.