<P> In the 1500s, Paracelsus was probably the first to criticize Galen publicly . Also in the 16th century, scientist and artist Leonardo da Vinci compared metabolism to a burning candle . Leonardo did not publish his works on this subject, but he was not afraid of thinking for himself and he definitely disagreed with Galen . Ultimately, 16th century works of Andreas Vesalius, sometimes called the father of modern human anatomy, overturned Galen's ideas . He was followed by piercing thought amalgamated with the era's mysticism and religion sometimes fueled by the mechanics of Newton and Galileo . Jan Baptist van Helmont, who discovered several gases such as carbon dioxide, performed the first quantitative experiment . Robert Boyle advanced chemistry . Sanctorius measured body weight . Physician Herman Boerhaave modeled the digestive process . Physiologist Albrecht von Haller worked out the difference between nerves and muscles . </P> <P> Sometimes forgotten during his life, James Lind, a physician in the British navy, performed the first scientific nutrition experiment in 1747 . Lind discovered that lime juice saved sailors that had been at sea for years from scurvy, a deadly and painful bleeding disorder . Between 1500 and 1800, an estimated two million sailors had died of scurvy . The discovery was ignored for forty years, after which British sailors became known as "limeys ." The essential vitamin C within citrus fruits would not be identified by scientists until 1932 . </P> <P> Around 1770, Antoine Lavoisier discovered the details of metabolism, demonstrating that the oxidation of food is the source of body heat . Called the most fundamental chemical discovery of the 18th century, Lavoisier discovered the principle of conservation of mass . His ideas made the phlogiston theory of combustion obsolete . </P> <P> In 1790, George Fordyce recognized calcium as necessary for the survival of fowl . In the early 19th century, the elements carbon, nitrogen, hydrogen, and oxygen were recognized as the primary components of food, and methods to measure their proportions were developed . </P>

A food that provides health benefits beyond its nutrient contribution