lemon is alkaline forming in the body and aids in digestion. You body works to balance the ph when you digest food so your blood remains slightly alkaline but if you eat a lot of foods that have an acidic effect after digestion your body has to use up a bunch of the minerals to balance the ph. So you get weak bones, you maybe get fat, lethargic and just generally have a bunch of problems. A lot of food is acid forming so its just a good idea to add a few drops of lemon to your water to aid in digestion. Also don't eat acid forming foods that also don't have much nutritional value like fried food and soda.