@Ezra. Your answer is both right and wrong. The body does need sugar to survive, mainly because the brain can only metabolize glucose (a simple sugar molecule). Other organs prefer glucose but they can also utilize ketones (and some organs can utilize fat directly). However, a human can survive ingesting only protein (without “sugar”) since the amino acids in protein can be broken down and converted to glucose, glycogen (the long term storage form of glucose) and fat. Essentially, we have the capacity to synthesize our own sugar, and do not require any “sugar” or carbohydrate ingestion to live. As an aside, this in a nutshell is the basis of the Atkins diet.