Lemon is a Green food. Green foods are safe to eat as a regular part of a diet.
Guideline related quotes related to Fruits-Low-Fructose-Low-Glycemic and Green throughout Geoff Bond's publications.
Eat at least six pieces (servings) of fruit per day, focusing on “Green” and “Green-Amber” fruits. ~Paleo in a Nutshell p.102
Restrict total fruits consumption per session to three servings. ~Paleo in a Nutshell p.102
Specific references to Lemon throughout Geoff Bond's publications.
Water should still be the main drink; try carbonated water with a twist of lemon. Unsweetened tea, iced or otherwise, is also okay. ~Paleo in a Nutshell p.107
Jacob Schweppe, a jeweler in Geneva, read Priestley's papers and, by 1794, was selling highly carbonated waters to his friends. He added other mineral salts and flavors, such as ginger, lemon, and quinine (to make tonic water). Schweppe moved to London and built a worldwide soft drinks empire. ~Deadly Harvest p.78
Acids are compounds that taste sour and eat away at metals. Examples are the citric acid in lemons, acetic acid in vinegar, and sulfuric acid in car batteries. Alkalis (also known as "bases") are the opposite; in a way, they are the antidote to acids. For example, the stomach contains hydrochloric acid, which sometimes causes indigestion; the antidote is an alkali (or "antacid"), such as sodium bicarbonate and magnesium hydroxide. When acid and alkali cancel each other out, the result is neutrality— the blood is neither acid nor alkaline. ~Deadly Harvest p.108
Water should still be the main drink; try carbonated water with a twist of lemon. Tea, iced or otherwise, is also okay. ~Deadly Harvest p.183