I would like to give you a succinct answer, but I am not as well spoken as Robert Lustig, MD, a Professor of Pediatrics in the Division of Endocrinology at University of California, San Francisco, and the author of Fat Chance: Beating the Odds against Sugar, Processed Food, Obesity, and Disease.
Is a Calorie a Calorie? Processed Food, Experiment Gone Wrong
Presented by Stanford Health Care
https://www.youtube.com/watch?v=nxyxcTZccsE