Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847. Pure, dry fructose is a very sweet, white, odorless, crystalline solid and is the most water-soluble of all the sugars. From plant sources, fructose is found in honey, tree and vine fruits, flowers, berries and most root vegetables. In plants, fructose may be present as the monosaccharide and/or as a component of sucrose. Commercially, fructose is usually derived from sugar cane, sugar beets and corn and there are three commercially important forms. Crystalline fructose is the monosaccharide, dried and ground, and of high purity. High-fructose corn syrup (HFCS) is a mixture of glucose and fructose as monosaccharides. Sucrose is the third form. All forms of fructose, including fruits and juices, are commonly added to foods and drinks for palatability, taste enhancement and improved browning of some foods, such as baked goods.

Robert H. Lustig, MD is Professor of Clinical Pediatrics, at the University of California, San Francisco (UCSF). He is nationally recognized in the field of neuroendocrinology, with an emphasis on the regulation of energy balance by the central nervous system. He has a special interest in childhood obesity. He has become publicly notable through his efforts to draw attention to the effects that the natural sugar fructose can have on human and especially children's health if consumed in large amounts. On May 26, 2009, Lustig gave a lecture called “Sugar: The Bitter Truth” which was posted on YouTube the following July and has become a viral success with over nearly 2.5 million viewings (as of Jun 2, 2012). In this lecture, Lustig notably calls fructose a "poison" and compares its metabolic effects with those of ethanol. Lustig is particularly critical of the widespread use of high-fructose corn syrup in the United States.

Lustig grew up in Brooklyn, New York, and attended Stuyvesant High School in Manhattan. He obtained his bachelors degree from MIT in 1976, and received his M.D. from Cornell University Medical College in 1980. From there, he spent six years as a research associate in neuroendocrinology at The Rockefeller University. He performed his pediatric residency at St. Louis Children's Hospital, and his clinical fellowship at UCSF which he joined in 1984.

Bad news may refer to: